MG Midget and Sprite Technical Clutch problems BBS discussion at MG-Cars.info

MG Midget and Sprite Technical - Clutch problems

1098cc MKII Midget. Does anyone have any ideas on what this problem might be: On a drive last week the clutch started to play up; fully depress the pedal, engage gear, and the bite was right at the extremity of full stroke, and the bite was very, very short. This was on first and reverse, not so noticeable on second and above. Quite a difference from the normal positioning, felt like it was only just depressing the clutch. No leaks around the slave or M/C, nice positive pushrod action when the pedal is depressed so no problems there. Adjusted the M/C pushrod to give quite a bit more travel, took it for a spin and the gear changes felt the same as before I had increased the pedal stroke, so very little control. On a couple of instances in first gear, I just revved the engine and the car moved off without me releasing the clutch pedal at all. Can anyone suggest what could cause these symptoms and does this suggest that perhaps the fork has bent or the clutch cover has failed?

Philip Sellen

Clutch fork pivot pin? Leaking slave seal? Also I believe that the fork itself can crack adjacent to the drilling for the pin and subsequently bend. Although I've never seen it personally. Just guesses.

Greybeard

Thanks Grey, The slave is dry and moves very positively when the pedal is pressed. I hadn’t heard of the fork cracking, but I’m aware that it’s been reported they can bend/deform. What a pain, when I should be driving it.

Philip Sellen

Phil If you put your foot on the clutch pedal and then the car drives off it points to a faulty seal in the master cylinder. There wont be any outside evidence.

Alan Anstead

"perhaps the fork has bent" Yes, they do bend. I remember I had that a couple of times before I switched to a type 9 box and concentric release. I think I have pictures. I'll look tomorrow. Meanwhile, here's a thread about it. https://www.mgexp.com/forum/mg-midget-forum.3/straightening-bent-clutch-fork-in-place.3643263/ And google search results. Link shortened. https://tinyurl.com/mry23b39 Also, a REALLY worn carbon might cause it too.

anamnesis

Anam, I have one of Alan’s roller release bearings, so thankfully I can rule out the bearing itself. Alan, I’ve not heard of this symptom before? With the pedal fully depressed, I can see pretty good extension on the slave pushrod - which holds its position. Under these circumstances, how could the gear then be engaged so I can drive off? The symptoms remained the same after I increased the pedal stroke, I was expecting to see a difference in the clutch. Don’t get me wrong, I’d much prefer to change the seal rather than take the engine out, I’d be happy with that. Is there any other way of confirming what you’re suggesting? Thanks.

Philip Sellen

Philip Given that the pushrod is moving normally, it does sound like either a bent fork or a badly worn pivot bush but you wouldn't expect either to happen suddenly. Pivot bolt loose or half out maybe? Worth looking through hole in top of bell housing or getting a picture on mobile or with endoscope if you have one? I havent one and am in southern Spain on road trip right now so can't help I'm afraid Philip.

Bill B

The slave pushrod only needs to move about 11mm. (It would probably be 1/2" by design) So it's possible to check that whilst someone presses the pedal for you. Put a flag of masking tape on it and then measure the distance it moves. If the clutch fork is bent, two possible situations might hinder this movement. The fork could come up against the edge of the bell housing cut out. Or. The slave piston could meet the end circlip (if it has one) before the clutch has fully disengaged

GuyW

Bill: The pivot bush was new just a few thousand miles ago, if the bolt is loose - that’ll be down to me not properly tightening it. Very difficult to get a good shot of the fork from either the top or bottom opening. An endoscope is the way to go but I haven’t got one either. Guy: Thanks for the different scenarios regarding what’s likely to happen when the fork bends. I’ve got probably more than 1/2” travel at the slave, which appears to hold its position when depressed. I might get a cheap endoscope so I can maybe confirm what’s going on in the bell housing before I commit to an engine out exercise.

Philip Sellen

Phil It was probably in my teens and with my father’s Hillman Minx. Foot on the floor for the clutch and the car would move off. A rubber in the master cylinder was pushing the fluid forward, to disengage the clutch, but then letting it past and allowing the clutch to engage? 1275 clutch yokes usually bend where the arm narrows just before the clevis that attaches to the clutch slave rod. If laid face down with the spigot U’s facing down a 1275 yoke should lay flat on a flat surface. If you think your yoke is bent or the fault is with the clutch actuating rod you can put a small washer between the rod and in the recess of the slave piston hollow to extend the rod as a trial / demonstration.

Alan Anstead

Thanks Alan. I extended the travel on the slave push rod and it made no difference to the symptoms I’m experiencing with it. The slave push rod appears to be holding its position when kept depressed. I believe my 1098 and the 1275 forks are one and the same, so your comments regarding distortion will relative to mine.

Philip Sellen

Sorry, lecture warning alert! Philip, it took me a good long while to realise the following, but once understood it does help in understanding the Spridget clutch system. It may not itself give you an answer, but it may help. When you take your foot off the clutch pedal it is the clutch cover plate springs which cause the train of actions, not the pedal that you have been pressing with your foot. Obvious, but the clutch springs push the thrust bearing back, moving the fork, the slave pushrod and therefore the piston back up inside the slave cylinder. Nothing else moves the piston back. The piston movement forces the hydraulic fluid back up into the master cylinder. Springs on the pedal / master cylinder are just 'helpers' to take the weight of the pedal and to stop it rattling! Maybe thinking through each of those steps might throw up something that is preventing the clutch from releasing? So, in your case if the clutch is 'dragging' when your foot is down on the pedal, then something is impeding that train of movement preventing the clutch driven plate from freeing from the flywheel and cover plate 'sandwich' Starting with the plate itself it could be snagging on the shaft splines. Some plates can start to dismember, with the friction material or rivets distorting so effectively the plate becomes thicker and drags on the flywheel, even when de-clutched.

GuyW

If there is too much travel in these clutches at the pushrod, the retaining ring for the pressure pad can come into contact with the centre of the plate and push it onto the flywheel, causing drag. Easily tested for by easing the pedal out a little and seeing if it the gears can be engaged. Counter-intuitive but true! However, I have found this only with new-ish clutches and have suspected over-thickness linings, so as your fault has developed recently after being normal I wouldn't expect it to be the case here. The most common cause of over-stroking a 1275 is when fitted with the (smaller) 1098 slave. I'm not 100% sure of what the 1275 stroke should be other than I don't think it is more than 11mm - it certainly still works at 9-10. So more than 1/2 inch as mentioned above is more than adequate. That being the case there's nothing left to do than pull the engine and see which of the faults Guy lists is the culprit. Or whether it is one of the strange but true foibles tgat plague us from time to time.

Paul Walbran

After-thought. Over-stroking dresses the diaphragm and can cause it to fail, either split (losing drive) or collapse on one side (causes drag). Have seen this as a long term effect of 7/8" 1098 slave instead of 1" 1275 slave.

Paul Walbran

*streses 😂

Paul Walbran

Thanks for your comments Paul and Guy. I don’t pretend to understand exactly how these thing work, I learn as I go along so your thoughts are appreciated. I’ll be acquiring a endoscope shortly for a look inside, but I know it’s more than likely going to be an engine out task in the near future.

Philip Sellen

Peter, from your first post in this thread. "-- felt like it was only just depressing the clutch. " This is a picture of a significantly bent fork in situ before 'straightening', with the release bearing sitting against the clutch cover(pad). The 2nd picture is after straightening. Is your fork arm 'close' to the rear of the bell housing hole? Obviously the more bent it is, the less you'll depress the clutch. Bent in the extreme, the fork arm will hit the rear of the hole, and would feel 'solid' to your foot on the pedal. Get someone on your pedal, to hold it fully down, or for example, hold it fully down with a length of wood under the steering wheel; and then get underneath to look at the position of the fork arm relative to the centre of the hole. Take note/picture of the position of the arm relative to the centre of the hole. Then detach the fork from the slave rod, slide a length of steel tube over the arm, and see how much farther you can move it rearwards to depress the clutch. Does it hit the rear? A better picture of a 'normal' unbent arm in situ, with the release bearing sitting on the clutch cover pad, might be very useful. I can't find one. Could someone oblige? It might save you an engine out job by definitely elliminating the fork/arm. Or confirming it, so you know you won't be on a fool's errand. The fork arm is surprisingly malleable. It's easily bent, which is why finding threads and discussions about it is so easy. To straighten mine, I hammered it flat. No heat applied. If you could heat the fork arm in situ, I wonder if it could be bent forward using a bit of steel tubing as a lever. But even I wouldn't chance it, as it would risk snapping the fork mounting lugs.

anamnesis

On the other hand. "Straightening Bent Clutch Fork In Place" It can be done. "By removing the fork boot and putting a short piece of pipe behind fork, I was able to use a pair of vise grips to straighten it by pushing against the pipe. " "Clutch works great. Glad I didn't have to pull the engine/transmission." https://www.mgexp.com/forum/mg-midget-forum.3/straightening-bent-clutch-fork-in-place.3643263/ Clever. I'd definitely give that a go if yours is bent. Pretty well no risk to the mounting lugs.

anamnesis

They bend below the pivot pin, on the arm not the fork. A flat one and a bent one from our own archives. Thread: Clutch slave cylinder arm. Technical archive June 2012. https://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&access=&mode=archiveth&subject=97&subjectar=97&thread=2012061019180318042

anamnesis

" Obviously the more bent it is, the less you'll depress the clutch " I dont think that this, on its own, is true. It is only if by being bent the arm comes up against the rear edge of the bell housing hole before the clutch release bearing has moved forward enough to compress the clutch springs. Or: Being bent, it doesn't push the slave cylinder piston far enough back up the slave to provide enough travel the next time you press it, so the piston hits the end circlip (or pops out if there isnt one!) when you next press the pedal. This can be 'cured' up to a point by lengthening the pushrod, most easily achieved by slipping a 5/16" nut between the end of the pushrod and the inverse cone shaped end of the slave piston. It will stay in position there under the dust cap and is a good easy test to try out.

GuyW

Given all of this, these hydraulic clutches are self adjusting by design. I think the clue is that the clutch quite suddenly stopped fully disengaging, making it hard to change gear. This is usually because air has got into the system if the fluid level has been allowed to drop. Or a sudden change because a component has broken, typically the thrust bearing has broken up. Other faults tend to be more progressive with gear changes getting steadily worse as a warning. I don't know about the inner workings of the master cylinder, but Alan, who does know about these things, suggests a master cylinder problem? You mentioned adjusting the master cylinder to increase the pedal travel. In doing so you still need to maintain the m/c pushrod clearance.

GuyW

Philip said, "I extended the travel on the slave push rod and it made no difference to the symptoms I’m experiencing with it. The slave push rod appears to be holding its position when kept depressed." Sounds to me like hydraulics elliminated. Guy said, with regard to a bent arm, "I dont think that this, on its own, is true." I know from experience it is or can be. If it's bent, either bend it lack, or lengthen the slave rod. But if it's bent enough lengthening the rod won't solve it. 10 minutes to get under it, and do the check I suggested. Proves or illiminates it.

anamnesis

I agree it's unlikely to be hydraulics - unless some quirk of the m/c as Alan mentioned, but didn't elaborate. I wouldn't know. Currently my money is on collapsed thrust bearing or bent diaphragm. Or a disintegrating or distorted driven plate due to overthrow. I too have had a bent clutch arm, and straightened it with a big hammer! The odd thing is the dual fault reported of clutch drag (difficult gear selection) and clutch slip which are normally opposites! Maybe I miss read that?

GuyW

It's a 1098, so shouldn't have a diaphragm. Also, one of Alan's thrust bearings, but I don't know how likely they are to fail. Having said that, Alan said on the other thread that he only makes a 1275 CRB.

Dave O'Neill 2

Ah, missed that vital line at the very beginning! 1098. In that case another possibility is one of the fulcrum adjusting nuts on the cover has unwound.

Paul Walbran

The bent fork arms I have experienced have been caused by owners extending the slave push rod either using the incorrect length one or adding nuts etc beneath the slave cylinder boot in an attempt to cure a dragging clutch etc. If it ends up being a little too much the carbon bearing having fully depressed the clutch is solid against the clutch cover and the hydraulic force of the master/slave pushes the linkage/ arm until the weakest part bends. As Guy noted the clutch should be fully adjusted automatically by the system. My brothers MGB had a centre plate break up and it caused the car to leap forward with the clutch depressed. It was only one of the thin plates joining the friction surface to the centre core. Will be interesting to see what Phil’s turns out to be. Best of luck sorting it out. R.

richard b

Thanks everyone. To address the points in chronological order:- Anam: I’ll need to check the fork to see if it’s bent above the joint with the push rod. That’s an interesting fix in-situ which, hopefully, I could utilise if needed. Guy: I did adjust the push rod for clearance at the M/C. Anam: I’ll need to get underneath and check as you say. Guy: When stopped at lights; depress clutch, engage gear, rev engine a the car moves away while I’m still depressing the clutch. Dave O: It is a 1098, and Alan does only make roller release bearings the 1275 however, in the early days he also made them for the earlier cars - that’s when I purchased mine. Paul: That hadn’t occurred to me at all. Whe I get my hands on the endoscope, I may be able to tell. Richard B: I intend to return the travel on the push rod to its former distance of about 1/2” - 10mm. I’m away from home at the moment so I’ll report back when I have news in a few days, either good or bad. Once again, thanks for your thoughts.

Philip Sellen

Dave O’Neill I have made 948 and 1098 release bearings in the past fitting a bearing and faceplate into the original CRB casting. No one has reported a failure of a 1098 release bearing. I basically stopped making them some years ago. However I occasionally make 1098 ones, to a different design, but none since 2023 which was for a 1098 clutch on a 948 that I was assisting in converting to a Sierra T9 Conversion. They are time consuming to make I don't recall which type Phil might have. Robin Human now provides roller release bearings for 948 & 1098. I now make the 1275 roller release bearing but again there have been no reports of failures. That is not to say that they cannot / will not fail. The top pic is a 2nd development bearing as I don’t have a picture of what might be called the Mk3. 1098 release bearings I usually mark in red. The 2nd picture is of a 948 bearing such as I use on my 948 Frogeye.

Alan Anstead

Philip, I had similar symptoms to yours and part of the problem was wear in the clutch pedal clevis pin (where it attaches to the master cylinder) and the hole in the pedal where where the clevis pin fits - was very elongated. There was enough slack to prevent the pushrod from operating fully.

Jeremy MkIII

Philip, sorry then for my misunderstanding. I had got the idea that the clutch was slipping when under power. I hadn't realised that this was with the clutch pedal depressed. Delete that bit! Another thought though. If you have a smart phone that will take video you can get a pretty clear record of the inside of the clutch housing as it operates - certainly a better view than one can get visually because of the restricted space and sight lines. I actually think it would be better than with the endoscope.

GuyW

Jeremy, in the past I have repaired the pedal holes to eliminate any slop that could be encountered, to keep the mechanism working precisely, so I think I can eliminate that as a possible cause. Guy, no need to apologise, my wording wasn’t the best. I have a smart phone so I’ll give that a go, thanks.

Philip Sellen

Yep, take a picture/video through the top inspection hole. That's a very good idea. I'd forgetten I'd done that when I converterted to a roller bearing. You should be able to see your clutch driven plate, and the roller release. Might give you a better clue as to whether you really have to pull your engine.

anamnesis

I suffered almost exactly the same symptoms as stated in the original post. At least I 'knew' the master cylinder was ok because that was a good quality new one. Lots of time, frustration and new parts later, the fix was replacing the seals in the clutch bore of the master cyl.

Karl Thompson

Actually from the symptoms, it could still be nothing more complex than air in the slave. You could still see the requisite 1/2" of movement, but there not being enough force (because of the compressible air) to fully compress the clutch cover plate springs.

GuyW

Thanks Karl & Guy, an image/video may well confirm one way or another.

Philip Sellen

Karl, how did you work out it was the seals in the end and not something else - or was that because you’d been through everything else?

Philip Sellen

Before doing anything else, I'd get under it again and observe,-- take pictures, a video, of the clutch arm and slave rod action as the pedal is fully depressed. Take measurements of how far the arm/rod moves. Then keep the pedal depressed for a good minute, and see if the rod sinks back into the slave cylider. Btw, have you tried pumping up the pedal? Does this give you a better clutch pedal action? And here's another simple check. Is the pedal getting full travel? Not uncommon for a carpet or mat to ruck up and stop full travel.

anamnesis

When I get back to it in a few days, I’ll do that Anam. I originally had about 10mm travel on the slave push rod. I increased this to see if I got better engagement of the clutch but no, it didn’t. I’ll hold the pedal in and see what happens after a minute, and report back on my findings.

Philip Sellen

Lol. It's like a murder mystery now Philip. And we want the next episode asap. 😃. Meanwhile, I should be doing a bit of work on my own, instead of seeking vicarious satisfaction from other people's fixes. 🤣🤣. I should be fixing a hole where the rain gets in And stop my mind from wandering Lol. https://youtu.be/UPBd8eHQqIw?feature=shared

anamnesis

It was the result of lots of reseach in the archive here and running out of other ideas.

Karl Thompson

Now I’m back home, I’ve had another look at the clutch problem as follows: A- CRB fork looks to be straight and not deformed. B- I’ve returned the pedal and travel back (as close as I can) to its original setting - 10mm on the SC pushrod/fork. C- held the pedal down for a minute and it holds its position. I would conclude from this there’s not a problem with the hydraulics and it’s mechanical in some way. Anyone disagree? The endoscope I bought was about as much use as a pair of scissors so it hasn’t helped with examination. I can only think now I’ll have to pull the engine and look at everything. I attach 2 images taken on my phone, they don’t really tell me anything but one of you might spot something. I can see what appears to be a bolt that’s undone - out of focus in the foreground. I don’t know what this relates to but I don’t think it’s the clutch cover and therefore not part of the problem. Any thoughts welcome.

Philip Sellen

I think the out of focus lose nut could be the lever arm pivot bolt locknut. Of itself it shouldn't cause your symptoms but the lever may flap around side to side more than it should. And if the nut eventually drops off it could cause a problem interacting with a fast spinning clutch assembly

GuyW

I've not measured a 1098 pushrod stroke but given the hydraulic ratio of 3/4 mc and 7/8 sc I would expect more than 10mm. For comparison, MGB also has 3/4 mc, but 1.1/4 sc. Which gives 11mm stroke. It does of course depend on how much stroke there is at the mc so doesn't directly translate. If you pump the pedal a few times does it change?

Paul Walbran

It might just be the picture angle but that fork doesnt look straight to me. Trev

T Mason

The symptoms you describe, high touch point and combined with the dragging clutch you mention ----If it happened suddenly as mentioned and if it were a diaphram style pressure plate that is exactly how they behave when the diaphram collapses/cracks---In saying that maybe there's a broken spring in your spring type cover, or as Paul mentioned maybe a finger adjuster has come loose and moved --willy

William Revit

Thanks for your observations everyone. Paul - 10mm is the measurement I had originally before it developed these problems, and would’ve been like this for a couple of decades. I appreciate what you’re saying and that’s why I increased the throw but the symptoms remained the same. William - I can see how that could well be the cause. Only option now is to lift the engine and gearbox and take a look.

Philip Sellen

Is that a drop of oil hanging off the CRB in the first photo. Could it just be an oily clutch? Rob

MG Moneypit

My roller release bearing that is fitted does not need the extra lubrication seen on its exterior.

Alan Anstead

Even if the clutch is oily, the problem is drag, not slip. Willy may be right with a clutch cover fault, not letting the friction plate free up.

anamnesis

A known fault with old Quinton Hazel clutch covers is with the release bearing pressure pad on the clutch cover. The retaining ring on the clutch plate side being badly swaged comes loose and can fall away jamming the clutch operation. I have had this fault. I have to use QH covers to showcase my popular roller release bearings as the Borg & Beck, & other covers, do not have a large enough hole to allow the Sierra T9 first motion shaft to pass through. This type of QH cover is now seemingly quite rare. I overcome the problem by tack welding the ring to the pressure pad.

Alan Anstead

Oily clutches can drag/grab as well as slip - rear main bearing seal weepage causing contamination of clutch plate surface?

AdrianR

An interesting point about rear scroll leakage. In the Mk1 WSM it says, on the rear main only, to use Wellseal on the joint before fitting the main-cap. There must have been, back then, a concern about seepage between main-cap and block. In the MK2 WSM it says to use Hylomar? I don't have later WSM to see what instruction is given but wonder who, nowadays, continues this practise. I certainly did on the build shown. I have had no contact with the 1/2 engine’s recipient since.

Alan Anstead

Oilon the clutch does cause grabbing/snatching, but not when you disengage; it's when you engage. I'd be really suprised if oil was causing the plate to 'stick' to the cover so much, as to prevent the gears engaging, and enough to move the car forward with the clutch pedal fully down. My money is on there being more wrong than oil on the clutch. Sadly though, whatever it is, it's engine out to diagnose and fix.

anamnesis

Re reading back through this, if you can depress the clutch pedal, stick it in reverse or low gear and then it drives off on it's own,-- With no visible fluid leaks from the clutch cylinders- IF it were the pressure plate as I originally thought it would be hard/impossible to get into gear at standstill. If it's ok to get into gear but then gradually drives off on it's own, like as in sitting at the traffic lights it starts to creep off, then it has to be the clutch master cylinder bypassing fluid internally---I'd start by rebuilding/replacing the mastercylinder --first/cheapest place to start. It can bypass internally without showing external leaks. willy

William Revit

Except Willy, philip said "Now I’m back home, I’ve had another look at the clutch problem as follows: C- held the pedal down for a minute and it holds its position. " Fluid can't be releasing the pressure. And he's already tried extending the throw. It seems to me, whatever is wrong, is inside the bellhousing unfortunately. But, given how relatively quick/easy it is to remove and strip both the master and slave, for a look at the internals, maybe that is worth a shot, before hauling the engine out. Even then though, if I'd made all the investigations Philip has, I'd be confident enough to take the engine out first. It's free other than time, and you get to discover the oil source, g/box or rear scroll. It's a mystery. https://youtu.be/hKDi6ym3Ny0?feature=shared

anamnesis

Willy - extending the throw made no difference to the symptoms, unfortunately. The clutch bite point is now right at full pedal extension and is minuscule in movement to engage the gear. These symptoms came on very quickly. I’m now part way through prep for lifting the engine, which might be by the weekend. I hope to find something when I open it up so the problem can be resolved. It’ll be annoying if I find nothing, and then you may well be right with your thoughts Willy.

Philip Sellen

I'd had clutch engagement/gear selection ever since rebuilding the car. The culprit turned out to be the replacement slave cylinders supplied by the usual suspects. Only since using an O/E Lockheed from Paul Hunt have the issues been resolved completely. It got to the stage where replacing seals in both cylinders could be done by touch but with only a small, temporary improvement each time. Hope you find something when pulling the engine and can resolve the problem but if nothing obvious then I'd be considering re-sleeving an old O/E slave to original spec and trying that.

Jeremy MkIII

When you get the engine out, look at the splines on the gearbox input shaft, and on the centre of the clutch friction plate. I've just recalled I once had a friction plate unable to move freely on the splines. The result was the friction plate effectively held against the flywheel because it was unable to move freely on the input shaft splines. That would exactly explain why your hydraulics are fine, and there is plenty of release bearing movement, and yet still enough contact between the flywheel and the clutch friction plate, to make the car creep forward and make gear selection difficult. Could be debris contaminating the splines. Or maybe the friction plate centre has come partly adrift or askew. We should run a bet on who's right. Lol. I'll put a virtual 10 quid on a sticking clutch friction plate, for whatever reason it's not free to slide easily on the splines. 😄.

anamnesis

Phillip--just to be clear ,you say the bight point is at full pedal extension --is that right down near the floor or right up the top---I have taken it to mean right down near the floor but just checking wording. I've learnt not to be 100% convinced with anything really- Could be p/plate, could be m/cyl but whichever way it goes I guess the oil leak needs fixing but then again it might be just that one drip-? coming from the front of the gearbox-(blocked breather/overfull-parking down hill on steep incline) won't be crank scoll,that's on the other side of the flywheel and there'd have to be a fair bit of oil floating around in there to get to be on the t/out bearing I'd be interested to know if the master cylinder is returning fully after releasing the pedal--if not that alone can cause a low pedal - While releasing the pedal with it's low bight point ,as the pedal is released further is it still normal weight/resistance to the foot right back up to the top or does it feel extra light Is that 10quid each for us an--could get expensive. willy

William Revit

Phil, the other thing useful to clarify is whether the pedal is rising right up to its normal position when you take your foot off the foot pedal? The clutch cover springs should be providing the force to do do this for almost all of its movement, relaying their action via the various components and the hydraulic fluid. The last little bit of travel is assisted by a return spring inside, under the top of the footwell. If you unhook that spring does the pedal still come back up, or does it stay down near to your low bite point?

GuyW

Anam: I’ll check for any debris. Willy: Yes, I mean that I have to fully depress the pedal to the floor. I think I’ve always done that, but the bite point is now right down there and requires almost no lifting to engage. Prior to this, there was a gradual engagement as you might normally expect. It’s not been parked on a steep hill. The master cylinder appears to be returning fully after releasing the pedal, and feels normal. Guy: The pedal seems to return to its normal rest position, even if I remove the pedal box return spring. ————— As I’m not as mechanically minded as many of you here, I wouldn’t have thought of some of the suggested checks so I thanks for your comments.

Philip Sellen

10 virtual quid Willy. Because we're all making virtual diagnoses. Lol. However one thing is certain, whatever the diagnoses, the prognosis, is good, as are the prognoses, should there be more than one accurate diagnosis. 😁. Good point Willy. If the bite point is on the floor, the fault may well still be between the pedal and the pushrod. But Philip said, "I extended the travel on the slave push rod and it made no difference to the symptoms I’m experiencing with it. " However, the pivot point on the fork, is such that another 5 mm pushrod movement, translates to much less movement at the release bearing. If the bite point is that low to begin with, another few mm throw at the release bearing could still be ineffective. I'm leaning back to a bent fork, albeit Philip has said not. It would be so much easier if we could inspect it ourselves of course. Now if you were here ---- 🙂 ---- So, so you think you can tell Clutch fluid from oil A bent fork from trapped air Can you tell a stuck pedal from a seized slave rod? A grab from a snatch? Do you think you can tell? How I wish, how I wish you were here We're just lost spridgeteers guessing at faults, tryin' to get it clear Running over the same old ground, what have we found? We hope we are near, wish you were here. https://youtu.be/rKT6Ye-aaqg?feature=shared

anamnesis

"Yes, I mean that I have to fully depress the pedal to the floor. I think I’ve always done that, but the bite point is now right down there and requires almost no lifting to engage." Different ball game Philip. Don't pull the engine -- yet. You need to find out why the bite is on the floor.

anamnesis

Ah but - that didn’t alter when I increased the travel on the pushrod.

Philip Sellen

Phillip - real early on in this you mentioned that you'd adjusted the m/c pushrod for more travel-- So what did you actually do there---some of these cars have adjustable stops on the pedal box, some have adjustable pushrods, some have both---Just interested in what happened there-- It's important to have a tiddle clearance between the pushrod and m/c piston at rest. How much clearance was there before you adjusted it and which way did you go-shorten or lengthen the p/rod-etc-? has it got clearance still. It's important to ensure the piston returns right back and has clearance. If not the cylinder bore can't refill properly and the pedal will operate lower than normal and won't be able to be pumped up at all . I'm thinking you need to pop the boot off the end of the m/cylinder and make sure the piston is returning right back and not stuck up the bore a bit. Adjusting the bottom slave cylinder rod length does nothing apart from moving the operating are of the piston to another spot-- The only reasons for changing the length of that are that either the piston is sitting right back against the end of the cylinder at rest(needs shortening) or the piston is getting close to popping out of the housing when operated (lengthen the rod) willy

William Revit

Bite point near to the floor is typically air in the hydraulics, and nothing more than that. But another possibility is if you have got a mis-match between master and slave cylinders. Without re-reading this now lengthening discussion I cannot remember if either of them has been changed? If you have ended up with a larger diameter slave, it will of course extend less far as pedal is pressed, so the clutch won't disengage until the pedal is down near to the floor.

GuyW

The importance, as Willy mentioned, of the mc piston returning fully in the bore is that it uncovers a small passage between the bore and reservoir that allows fluid into the mc bore.

David Billington

Now't has changed. Just a worsening of the low bite, that Philips says happened very quickly Guy. Philip, notwithstanding all that Willy says -- Have you tried pumping up the pedal? On the 27th May I asked Btw, have you tried pumping up the pedal? Does this give you a better clutch pedal action? You followed up with various checks, but no pedal pumping. Put your foot on the pedal. Gently press the pedal, and note where above floor level, you feel the resistance increase. Then, again gently, without going all the way to the floor, depress and lift the pedal 1/2 dozen times or so in fairly quick succession, BEFORE pushing all the way to the floor. Does doing that, lift the point at which you feel the pressure increase under your foot, as the cluctch is disengaged by the release bearing. You won't be able to mistake it. If the pedal can be pumped up, it's a very noticable feel to your foot. Edit. You could even do it with your hand. You'll notice it even more then. If it does pump up, you may even just need a bleed. Or worst case, strip the hydraulics and inspect.

anamnesis

Willy: As Anam says nothing has been changed. No adjustment on the SC, for the MC I backed off the pedal stop bolt (cast iron combined MC) then took up the slack by screwing the MC clutch pushrod. This gave me a longer stroke at the SC pushrod. I endeavoured to ensure there was clearance/slack with the pushrod. Guy: Neither of them has been changed in many years, this problem came out of nowhere. David: Yes thanks. Anam: I have tried pumping the pedal following your instructions; the result is it feels the same as it did before.

Philip Sellen

Philip, with such a low bite, the clutch can't be being disengaged enough. The question is why. If you're really sure you've checked all you can externally, only the engine out remains. I'd say my sticky spline suggestion is redundant too now. I'll fall back on a bent fork, but there could be a couple/few different causes, but a cover fault of some kind seems a distinct possibility, linked to the low pedal bite. Are you in a garage, or on your drive?

anamnesis

I’m in my garage. 70 posts and nothing definitive has come out as a consensus on the likely cause. Nothing wrong with that and as you say looks like it’s time for engine out to see if anything is amiss (I hope so). Otherwise it’s back to the drawing board. If I can’t see anything obvious to me, I’ll need to get a pair of experienced eyes on it for a more considered opinion. I’ll let you all know in due course what my findings are.

Philip Sellen

Not so bad then having a garage to work in. Is anybody near enough to Gloucestershire, that you could invite over for an 'experienced' eye over? Club member? Philip earlier you replied to Willy: --- Yes, I mean that I have to fully depress the pedal to the floor. I think I’ve always done that, but the bite point is now right down there and requires almost no lifting to engage. Prior to this, there was a gradual engagement as you might normally expect. When did Alan's roller release bearing go in? Did you have a low pedal bite point before the roller release was put in?

anamnesis

Before taking the engine out, I think there remains the possibility that's it's master cylinder related. I remember Alan Andstad suggesting this as a plausible cause right back early on in the discussion. That said, if it is engine out it's a pretty quick and simple in these cars. An hour's job out and maybe a little longer back in. I remember doing it 4 times in one day when settling in my T9 !

GuyW

Given that the slave pushrod seems to move sufficiently (11/12mm ?) and the fault happened suddenly, my money is on a clutch cover fault. I haven't seen enough of them though and haven't had this problem so I'm not an "experienced eye".

Bill B

Bill, that makes sense but I still have my money on a bent fork because as I said before it still doesnt look straight to me in that photo. Trev

T Mason

Anam: The roller release bearing went in 2 or 3 years ago, and I cannot remember the clutch feeling any different before or after. It felt very seamless. Guy: Your comments made me smile. Unfortunately I don’t possess that level of skill or experience to make it that quick an exercise. Trev: I think I’d be happy with that - should it be the case. Resolution would be satisfying. If it is bent, I think Guy said he just hammered it back to the correct profile. Is this a long term solution or is it likely to distort again in the not too distant future?

Philip Sellen

Mind you Trev, when I extended the travel wouldn’t that have countered any bend in the fork. The result of that adjustment by me made no difference to the clutch.

Philip Sellen

Yep just hammer flat again. No heat required. And it will last. If that's what it turns out to be, and your worried, you could have a 'stiffner' bar welded behind it. Dave O mentioned racers doing that I think. It is easy as Guy says. Engine out on its own. Give yourself a weekend. Oodles of time. Assuming of course the problem is simple and you don't have to order any nee bits and wait for delivery.

anamnesis

Although I consider myself to be a Luddite with regards to computers and portable telephones I have recently used Messenger Facetime to assist someone ‘up t’north’ and another in France with Sprite & Midget problems. It does allow for examination of components close up that photographs don't always convey. I also made a short video, for the chap in France, to show an assembly sequence that I could e-mail to him although, not for the first time, I will probably have to travel to France to fix his car myself.

Alan Anstead

You may be inadvertently setting yourself up for a visit to Gloucestershire Alan. 😉.

anamnesis

Phillip--sounds like you've done the pedal/cyl adjustment correctly, I was a bit worried that you might have just wound the pushrod in---all good there, I'm leaning towards a p/plate issue, but still think that you need to pull the dust cover off the m/cyl and check that the piston is coming right back just in case, should be able to see it through the pushrod hole or even take the endplate off and slide it along the pushrods then you could get someone to operate both brake and clutch to compare their operation/returning positions Don't worry about the 70 posts , we like a good story here--lol

William Revit

Willy and others, This is the situation regarding the internals. Having loosened the end plate, I can see the seal coming back flush with the MC casing. When the pedal is activated then released, the seal immediately returns to this position. I’m thinking this look alright, do you agree?

Philip Sellen

Not sure that tells you much Philip. It's the internal seals you need to see. That said, the rod is dry. No sign of fluid seeping out, so that's good. Been a good while since I was close up with the earlier pedal box. Needs another opinion.

anamnesis

Phil You are good there. At this point let me repeat the unusual fault that befell my late father’s car. Imagine you push the clutch rod into the master cylinder. The rubber seal pushes the fluid to the slave and that acts upon the yoke and subsequently the clutch. But the seal collapses letting fluid back into the reservoir. There will be no external evidence of this dastardly deed. With fluid returning to the reservoir the clutch will be release and the car will mysteriously move away. The only way to check is to have one person operate the master cylinder whilst another watches the slave. Best jack the rear wheels off the ground so that a gear can be chosen and the wheels left free to rotate.

Alan Anstead

Okay thanks Alan. I've observed the action of the slave whilst someone operates the pedal, that all seemed good. And the slave piston held its position for a minute when the pedal was depressed. However, I haven't tried the wheels of the ground in gear exercise. I'm Now pretty close with prep to removing the engine so I might as well commit to that then at least I can remove all doubt (hopefully) that nothings wrong in there. If that's the case then it looks like it'll be a MC refurbish. Do Past Parts still service these units do you know?

Philip Sellen

Afaik Past Parts are still re-sleeving bits. Haven’t used them in a while because their work is so good. That said everything can change as I am being hounded out of Masc by the toxic twosome!

Alan Anstead

Although I suggested the clutch cover/ release mechanism, you don't tend to hear of them failing. But, from what Philip says, it doesn't sound hydraulic even though that is fairly common. If so, the release bearing is too far back which points to a bent release arm/ fork as Trev says. Gee, this is intriguing!

Bill B

Although I didn't explain why, I asked if the pedal came fully up even with the 'assist' spring in the footwell disconnected. Phil confirmed that it did. My thought behind this test is that the pedal is ONLY pushed back by the clutch cover springs, acting via all the intermediates. (unlike, for example, a MMinor clutch which has a pull back spring hooked onto the clutch lever arm, though probably more to stop rattles as otherwise the systems are basically the same. So if the pedal rises up reasonably sharply when you take your foot off, it suggests that everything in that train of intermediates is working. The fluid is being pushed back up to the M/C and there is still sufficient on the correct side of the piston seal to lift the pedal, refilling the cylinder ready for the next stroke. It eliminates quite a lot of small crimson fish! Even king ones, Annam 😂

GuyW

And a photo of my set up on a CI dual cylinder, (MK1) though with no guarantees that this is correct! Screwdriver points to the 3mm clearance.

GuyW

Fish Guy? 2 Parrots clutching onto a perch, wondering where the fish smell is coming from. 😉.

anamnesis

Red herrings, Annam. Not crimson perches. https://m.youtube.com/watch?v=ukgraQ-xkp4

GuyW

Good band Guy. I'd completely forgotten about them. But fish? I still don't see the connection. Lol. You'll have to enlighten me.

anamnesis

...PERCH... (Those poor kittens. Explaining a joke is like drowning a kitten they say).

Greybeard

Lol Grey. The perch joke was mine. I was asking about Guy's 'crimson' fish.

anamnesis

LOL. Annam. Crimson fish = red herrings. I had described a procedure for clutch checking (no eggs involved) that eliminated them. But I do like the smelly parrot joke. True story, once walking on a riverside path near Elterwater in Langdale, I commented to wifey that I could smell dead fish. 30 yards on was a bench so we sat for a while. As we stood up I noticed the engraved plate on the seat back : RIP David Fish.

GuyW

Ah right Guy. My brain must have been in dim mode not to have got that. Lol. Very good. That's a funny story. Made me laugh. Maybe DF was haunting the plaice Guy 😉.

anamnesis

Maybe DF was haunting the plaice. Did think if I was arranging to get the plaque for the bench engraved I would have done it: In memory of David Fish Who loved this plaice Sorry Philip! Back to confusing contrary clutches.

GuyW

Au contraire Guy, it’s good to occasionally lighten the discussion.

Philip Sellen

Philip, I've scan read through all the comments and maybe I don't have the full story. I read that you have the Alan release bearing, has the clutch pressure plate been modified so that the release bearing is pushing against the spring fingers of the clutch? If so, the pressure plate could be throwing the release bearing back further than it should, which means the slave piston needs more stroke to disengage the clutch. Make a L-shape bracket you can attach to the outside of the gearbox to prevent the fork from being thrown back further than it should. This might save you pulling the engine out

Nigel Anderson

No fingers on this cover I think. Looks like this type to me. Pad's still clipped firmly in place. Bearing is in contact. Philip, was this picture taken with the pedal at rest? I assume it was. Another picture with the pedal depressed would be, perhaps, informative.

anamnesis

Nigel: No modifications required for figment of the AA bearing, so unfortunately your suggested mod is a non-starter. But thanks for your input.

Philip Sellen

Anam: That image was at rest. I’m not in a position to capture it in use because it’s out of the car now. Hopefully I’ll be able to inspect the innards in the next couple of days or so.

Philip Sellen

Engine out huh? Good stuff.

anamnesis

Just to confirm. When using my clutch release bearings on 1275’s there are NO modifications necessary. The roller bearing engages on the clutch cover pressure pad. Out with the carbon release bearing, in with my roller release bearing, fit & forget - and enjoy. I have to visit the P.O.today to post another four such is the demand for my product. With full credit given to Barney Gayford and the MGA Guru site that he maintains : which is an amazing source of information he explains the symtoms of the self driving car that I have tried to explain happened on my father’s old Hillman Minx.

Alan Anstead

Nice product Alan. So nice, I almost wish I still had a rib case lol. If I were to go back to my rib case, I'd definitely go roller. Just a quick question. Did you retain the fork for your T9 boxes? Or are you concentric like me? On that creep explanation. Perfect sense. I've had exactly that myself in the past. It can happen on the later masters too. But in Philip's case, his slave push rod remains extended, and he says he has no ability to pump up the pedal. Hopefully, since he's engine out now, he'll identify a fault that explains his problem. 🤞🤞🤞

anamnesis

I’d like to add my support for Alan’s roller release bearings, I’m not expecting to find anything wrong with it when I open up the gearbox. I mentioned earlier that when I swapped to his bearing, the change was seamless. As Alan stated, it was literally fit and forget.

Philip Sellen

Anamnesis On my 1275 (Sebring Sprite) T9 conversion I retain the yoke to be able to ‘showcase’ my roller release bearing. However I have to use, a now difficult to source, Quinten Hazel clutch because it seems that only this brand has a cover pressure pad with a hole large enough for the T9 first motion shaft to pass through. Due to a known fault I tack weld the pressure pad and its fitting ring together. On my 948 (Frogeye ) T9 conversion I have converted a smoothcase bellhousing so that yoke and clutch covef can be used with my own brand roller release and a hybrid plate. Phil. Can you not get your steering rack alloy bracket Tig welded locally. I am sure if you posted it to The Machine-shop at Hinkley they would fix it for you. I cannot offer to assist as I am only Billy Basic with Tig on steel alone. ****. In the unlikely case of my release bearing being proven at fault you can consider it to still be under guarantee.

Alan Anstead

Thanks Alan. I'd better get a spare set of o-ring seals for my concentric slave while I still can then. Assuming I still can; I'd better start looking.

anamnesis

Which concentric slave are you using, Annam?

GuyW

Alan, I must admit I hadn’t even thought about that as an option. The answer is - possibly. I would’ve thought it couldn’t have been done precisely enough for future use but as you’re suggesting it could be, then that is an option. I will probably try to get a replacement as I’d like to get back on the road sooner rather than later but I’ll look into a possible repair. Many thanks for your suggestion. Still under guarantee! What sterling service you provide Alan, I wouldn’t have ever presumed any kind of recourse to you.

Philip Sellen

Titan/Saab/Burton Guy.

anamnesis

Annam, mine's a Ford one, mounted on an alloy block that I turned up on my old lathe, to fit over the T9 input shaft oil seal. Otherwise it's much as yours, though your pipework is neater!

GuyW

Lol. I thought my pipe work was a mess. I remember you posting a picture of yours, and it was very neat.

anamnesis

Looks like I can easily get new seals on Ebay. https://www.ebay.co.uk/itm/295206885681 But I baulk at paying 28 quid for 3 o rings. Pretty sure thereis a cheaper option.

anamnesis

Yep, this is better. 15 quid plus vat plus delivery. Which in the end is only 3 quid cheaper. https://raceandrally.com/viton-seal-kit-for-saab-titan-release-bearing-assemblies There are a number of 'us' who have this Saab type concentric slave in their T9 conversion. So hopefully this will be useful information. But everything is an arm and leg these days. Almost 6 quid to post 3 bloody o rings. How can it be right to charge va sodding t on the delivery too?

anamnesis

The last one mentions Viton, you might want to check chemical compatibility lists but IIRC the material of choice for normal brake fluids, if that's what you're using, is EPDM.

David Billington

Possibly Anam https://tinyurl.com/mv3vscwt Maybe not exactly what you're looking for but you can have a poke around the site? AFAIK it's the same c#ap as ebay but without the middlemen. The only catch is you need to spend £15 for free postage.

Jeremy MkIII

I put together my concentric before I discovered Burton Power, so chose the Ford version as being a good deal cheaper at the time, than the SAAB one. I've no idea if the seals are a repairable item. I suspect not, and one just buys a complete new unit.

GuyW

Thanks chaps. This is WAY better. After a look through my spares, I remember now. I replaced my seals as a precaution when I had the engine out in 2019. The old ones must have been nigh on 20 years old, and actually looked fine; I've still got the old ones kept as spares. I bought the new ones from Rally Design in Kent. 11.88 inc vat, and I collected them as I was down that way that day. They still sell the seals, and they are still £9.90 ex Vat £9.90 ex vat. £4.25 delivery, VAT: £2.83 Total: £16.98 https://www.rallydesign.co.uk/product_info.php?cPath=885_1883&products_id=13888 Just ordered; quite possibly I'll never need them. And I'd forgotten I bought a complete new spare clutch and release bearing; also as spares. I'm set for my future I reckon. 😁

anamnesis

Maybe doesn't apply to these specific parts, but if you join up my rotten rubber topic with this one, would one these days, buy a second spare 'for the shelf' if it had a rubber component? When I rebuilt the frog steering rack, about 4 years ago, I didn't buy a spare pair of rack gaiters. I suspect that if I had, I would still be needing to buy new ones now. Bill Mohan, who used to be a major frequenter of this BBS, put together a self build concentric at the same time as I did mine, using as I recall, a SAAB version like yours, Annam. Bill is still around, though on the other side these days. That might just wake him up!

GuyW

Ha. Well I hope the seals last. I've paid for them now. Lol. Still, I've always got my used o rings to fall back on. 🙄. If only we'd read the tea leaves, and realised back in the 70's and 80's, that we'd still own a Spridget circa 40/50 years later. We'd have bought shelf loads of all the stuff we need today when we had the opportunity, cheaper and best quality too. I often think/dream that, somewhere out 'there' is a derelict garage, or some old boy, sitting on a pile of original bmc Spridget spares, just waiting for me to discover it. 🤣🤣. There must be good quality rubber somewhere Got to be gaiters lasting longer in a rack at the ends If I can dream of better spares Where all new stuff doesn't fall apart Tell me why, oh why, oh why can't my dream come true Oh, why Dream on. Lol. https://youtu.be/u-pP_dCenJA?feature=shared

anamnesis

Attached and to follow are some images of the gearbox and clutch. I don't think anything is amiss but please correct me if I'm wrong. The fork looks straight to me - straight edges for reference. whilst there's a drip and a little wetness on the fork, the bearing is virtually dry as is the main shaft - just a thin black dryish film. The gearbox front cover and seal also looks dry in itself, the mess you can see is a wet smear over the front plate travelling down to the bottom but this appears to originate from the top most inspection cover area? I've had a look at the back of the engine and cannot see any wetness in that area? The clutch plate and cover appear very dry and I cannot see any damage or failure to any part of these components, so I guess they can be re-assembled on the engine. Suspicion must now fall on the MC which, although not presenting with any tell-tale symptoms, must surely need a full service. Is there a consensus that this is the way to go and I've not missed anything?

Philip Sellen

Phew! I can now sleep sound knowing that one of my release bearings has not let me down. Your Yoke appears to be straight as a die. It looks as if your M/c may have that obscure seal fault that I identified.

Alan Anstead

The slave piston/pushrod can't have been moving far enough then.

Bill B

I’ve uploaded other images but they’re not visible at the moment.

Philip Sellen

2 more.

Philip Sellen

Another couple.

Philip Sellen

Some more.

Philip Sellen

Does the clutch cover centre wear look uneven do you think? I’ll take another look at the components hopefully tomorrow but Alan, in no way has your bearing carrier failed.

Philip Sellen

Seems unlikely, but maybe you should check the flywheel for run out?

GuyW

Yes, all looks good. Compare new clutch cover, and yours. May be just the light, but in the lower sections of your pictures, the *friction* plates, both sides, look 'darker' or 'scuffed'. Makes me wonder if Guy has something with flywheel runout. But failing that, back to external components and hydraulics. Whoops, sorry for encouraging you to pull the engine. 😬😬 But you say the pedal wouldn't pump up, and that the slave push rod didn't retract even after a minute when under full pedal pressure. So, as Bill says, "The slave piston/pushrod can't have been moving far enough then." Is that a hydraulic issue or a mechanical issue? With a straight fork, are you SURE you have the correct slave cylinder rod length? And SURE you have the correct slave cylinder/master cylinder match? I'm stumped, and would love to be there to unstump me. 😅😅.

anamnesis

Surely, it must be the correct slave as it was working properly, previously? But, clearly, something has changed. A m/c rebuild seems the best option in the absence of any obvious fault.

Bill B

Clutch pedal action was always close to the floor. This suggests a mismatch or 'wrong' part. Maybe only a small change is all that's happened, but that was enough.

anamnesis

Anam: It’s difficult to work out if it’s hydraulic or mechanical as there are no definitive red flags. With respect to the correct components; the system has been working without any problems whatsoever for the last 20 years, so I can say it must have the correct setup for the car. Bill: Yes, as my comments above. Clutch pedal close to the floor - I think I have always fully depressed the pedal, normally the bite point would be a little way above that (a bit difficult to remember now as it’s been a while!). When this problem started, the bite point became right at the bottom of the pedal travel and was/is very small.

Philip Sellen

Philip Just to be clear, can you verify the slave is 7/8" which is correct for a 948 and 1098 engine AIUI.

Bill B

Please correct me if i'm seeing things but hasn't the pad that the throwout bearing operates against collapsed and sunk into itself--looks completely stuffed to me----A clutch reco joint would be able to replace just the pad. The way it's gone out of shape would most likely be causing your issue.-

William Revit

Ah... Philip, could you post a couple more pictures of the clutch cover, one side on and another "three quarter" view ( like the picture of the new clutch from Anam).

Bill B

With the cover and plate bolted on to the flywheel, is the pad parallel to the flywheel or does it have run-out?

Paul Walbran

Don't think it'll be running too straight Paul--I've tried to enlarge the pic but this is as far as I can get it---it's stuffed, looks like it's gobbled the pad up and poked it through the hole----

William Revit

<< Actually from the symptoms, it could still be nothing more complex than air in the slave. You could still see the requisite 1/2" of movement, but there not being enough force (because of the compressible air) to fully compress the clutch cover plate springs. >> Of course there could still be more than one problem. It could be the M/C problem that Alan identified early on. This, combined with not fully clearing air when bleeding, which would give the low pedal bite point. What is your bleeding procedure, if you will excuse the apparent colloquialism?

GuyW

Are these okay Bill? I would have fitted the slave many years ago and it’s been working fine since then. I could try and get a calliper in to measure the bore. I’ve arranged for someone with far more experience than myself to have a look at the components tomorrow. This person has viewed the images but cannot work out what’s wrong (like the rest of us) so wants to see first hand. Paul and Willy; I don’t think anyone else has mentioned that. I’m not knowledgeable enough to give you a comment on it but hopefully after tomorrow I may be able to shed some light on it. Guy; yes, I have it in mind that there may be more than one problem to deal with.

Philip Sellen

The pictures are useful Philip. Willy, Paul and your experienced guy tomorrow will give a more qualified opinion but, from those angles, it does look OK to me.

Bill B

Well wait and see what your advisor tomorrow says. But how confident are you in the clutch bleed that you did? Many seem to struggle with this aspect.

GuyW

Those photos are much clearer. The marks on the pad were a bit confusing when viewed head on.

Dave O'Neill 2

Yep. The cover looks fine, I thought so when I posted my new cover picture, alongside Philip's cover. Remember, the release bearing travels along an arc as it approaches the cover pad. Therefore it wipes an offset circle, and leaves the marks we see. Although, they are quite 'dark' marks, as if burning, or something. I also wondered about the friction plate, and the potential flywheel runout Guy suggested. That's still an open question isn't it? But everything we can see, elliminates almost everything else we've thought of inside the bell housing. So I'll repeat Bill's simple statement. --- "The slave piston/pushrod can't have been moving far enough then." Full circle, and yep a simple bleed may be the only issue, even though the pedal can't be pumped up. But assuming the 'bite point' has ALWAYS been too close to the floor, and it sounds like it has been even before the clutch dragging started, then something is amiss.

anamnesis

these two pics are of the same p/plate, my eyes are playing tricks on me. Pic3#1 looks like the pad has imploded- pic#2 looks better but still shows off centre wear. As Paul suggested it needs bolting up and checking for square. That first pic still looks really weird to me and my eyeballs--It must just be the light/angle but it looks like the centre has pushed through the pad to me and my head won't let me unsee that. Will be interesting to see what the touchy/feely man says------ willy

William Revit

Yeah, optical illusion Willy. I reposted one of Philip's clutch cover a few days ago. It shows the cover bolted up in place, and the release bearing sitting against the pad on the cover, with the pedal at REST. So the pad on the clutch cover isn't pressed in. But I agree, the marks look offset for the reasons I explained, they also look 'burnt'. But since Philip hasn't reported any noise, or any graunching/grinding you feel through your foot when there's a problem with the release bearing or pressure pad on the cover. So I reckon it's safe to assume those marks on the pressure pad are unimportant. The pad isn't being depressed enough. Why?

anamnesis

I dont think this is anything to do with the problem, but why doesn't your clutch release bearing have the little retaining spring clips? I thought they all had those. Opportunity to add them before reassembling?

GuyW

As I recall, these were the retaking clip that were available at the time. I know you usually see the spring wire type but these seem to have done the job okay. With reference to bleeding the system - I haven’t as there doesn’t appear to have been a need up until now. The pedal was good, the SC pushrod held its position under pressure, and it gave a responsive action when the pedal was depressed.

Philip Sellen

I know those clips, I had them on mine before conversion to roller and T9 concentric. !!!!!!! " With reference to bleeding the system - I haven’t as there doesn’t appear to have been a need up until now. " !!!!!! Uh oh. That looks very likely a strong, very strong contender. We've all worked on the assumption it had been bled. Bleeding 'ell you might say, after pulling the engine, if turns out, all it needed was to expel air. Gasp. 😅😅😉

anamnesis

We haven't all worked on the assumption it had been bled an. thing is this problem just happened during one drive so bleeding (or getting air) would be fairly unlikely---not impossible but.---- Could be a blocked up port in the m/cyl preventing cylinder refilling the same result as a sticking piston but that'd be fairly rare but then again not impossible. Still hanging to see what Philip's touchy/feely man can see--

William Revit

Guy Phil has the spring steel clips, not the wire clips, because he has my release bearing. The holes in the spigots are not drilled deep enough for the clips but allow me to dress and spigots on my lathe if the need arises.

Alan Anstead

Thanks Alan. I remembered the wire clips, from before I went concentric, and on other cars. I didnt realise your release bearings used a different form. Phil: <<air in the slave. You could still see the requisite 1/2" of movement, but there not being enough force (because of the compressible air) to fully compress the clutch cover plate springs. >> that still leaves the odd creeping forward symptom, which is why I suggested there may be more than one fault - that being possibly related to the m/c issue that Alan described.

GuyW

Philip you replied to Jeremy, -- in the past I have repaired the pedal holes to eliminate any slop. How did you repair said hole? Could your repair have failed? Perhaps that would be why it was ok for ages, and then 'suddenly' not ok?

anamnesis

Pedal holes: I re-bushed them. I had a discussion this afternoon with an experienced club member for about half an hour, as we examined the component parts of the clutch and gearbox. In conclusion, he thought all parts looked good, with no red flags or queries on anything. No witness marks were evident and the level of wear was considered to be normal for the amount of use it had seen. So this is good and bad news; good to know nothing is faulty mechanically and there can be no doubt now that the problem doesn’t lie within the box. Bad news because that leaves the hydraulics, which haven’t really exhibited any typical symptoms of failure. As it stands I think the only option now is to remove the MC and look for a problem there and even if I cannot find anything, probably get it serviced. Past Parts will charge around £250 for re-sleeving etc. Before that I will take a look at the SC but again, no typical symptoms have presented themselves.

Philip Sellen

Phillip, you have had an awful lot of opinions on all sorts of possibilities! It must be quite wearing just trying to keep up with it all let alone sifting out what may or may not be relevant. But one more from me. Partly at least because I like the easy solutions first, if this were my car I would do a clutch bleed before doing anything else. I note you say "the hydraulics havent exhibited any of the typical symptoms of failure" but I would say pedal going down to the floor and a very low bite point are exactly typical of air in the system. Yes, as Anam says, rapid pedal pumping can build up some pressure and I gather yours didn't do this, but this is difficult to achieve and be effective if the pedal is very far down, as yours is. And typically air in the system doesnt happen suddenly - its usually progressive. But maybe Alan's explanation is behind that. And of course it can occur suddenly if air gets drawn into the hydraulics if the reservoir gets very low.

GuyW

IF i remember correctly ,pumping the clutch pedal doesn't make a lot of difference The brake half of the cylinder has a check valve making 'pumping up' of the brakes possible but i don't think the clutch side has that valve, it's just a simple piston with a cup and a return spring- I had thought earlier that the spring might have broken or rusted through as they can preventing full return but Philip proved that wrong by removing the plate and checking for piston return. Bit of a weird one. Being able to get it into gear ok then driving away on it's own points towards the cylinder bypassing inside but according to Philips testing the slave doesn't creep which sort of eliminates any bypassing, which sends us back to making sure that p/plate is good--Paul's mention of checking that the pad on the p/plate is nice and square with it and the driven plate bolted back n the flywheel needs following up when it's reassembled.

William Revit

Yes thanks Guy and Willy, it’s difficult trying to filter through everything mostly because the problem doesn’t point to a specific cause(s?). I’ll take a look at the SC next, not sure how to hold it together to bleed it now the engine’s out. A thought I had was perhaps the MC internal spring could have partially collapsed, causing the problems I now have. Clutching at straws really (pun partly intended). I’m in Cumbria for the next few days so I’ll not be able to make any progress until next week at least.

Philip Sellen

Philip, When bleeding the clutch it can be difficult to fully expel the air. This can be down to the fact that the bleed nipple is right next to the pressure feed coming into the slave. Pumping fluid in can leave a good sized bubble of air isolated within the body of the cylinder whilst the fluid takes the direct short cut route out through the bleed nipple. An easy solution to this is to push the slave piston right back into the cylinder as far as it will go so there's little free space for bubbles to shelter in. Then secure it there whilst you bleed the system. I secure with a clamp and short length of dowel, but any arrangement like that will do. I would normally be doing this in the car, with engine clutch and gearbox assembled. But as the slave piston is jammed in it could be done with the slave hanging lose on the feed pipe, or as in your case attached to the gearbox. But until it's all back together you wouldnt know if bleeding had fixed the problem. I would add a remote bleed extension if you haven't done so already. Raining in Cumbria today!

GuyW

Definitely add a remote bleed if you haven't already. Guy prompted me to do it when I rebuilt the car and it makes bleeding much easier. I think I used the same flexible hose as used on the rear brakes, secured to one of the upper gearbox to engine bolts via a bracket.

Bill B

Apologies Philip if tis has been covered before but yours is a 1098 so is it the correct pushrod for the slave cylinder 13H21?

Jeremy MkIII

And yet more opinion. DON'T SPEND ANY MONEY YET. Put the engine back in, and do as Guy suggests. Bleed the clutch. Follow his instructions on how to do it. And yes the clutch pedal can be pumped up if there is air in the system. Provided you pump the pedal before all the fluid is returned to the master, you can pump more fluid down the line to the slave, which compresses the air further. As the air is comprrssed further, it gets denser, and less compressable, and so acts more forcefully. That's the point of pumping. It works. I know because I've done it myself on multiple occassions on multiple cars when I've been to lazy to fix a soggy clutch pedal, and a low bite point. So reinstall, then bleed. It really could all be as simple as that. I agree with Guy on this, simple option first, because it is often the simple fault that causes the problem. I for one, wrongly assumed it was all properly and fully bled prior to everything else.

anamnesis

Agreed, bleed the clutch. With a remote bleed pipe I found it easy. I was expecting trouble but didn't have any. However, I found my remote bleed was seeping fluid slightly the morning after I'd initially bled, but that seemed to help as I had a firm clutch pedal. Maybe the air had seeped out slowly overnight so, in effect, it had bled itself. Nipped it up and haven't touched it since.

Bill B

I left the slave hanging, so I might be able to bleed it if I can clamp the rod to the cylinder. Access is as good as it gets because I can “sit” in the engine bay. However, if no air is evident then it’s not the culprit in this long running saga and attention will turn to the MC. I’ll experiment next week.

Philip Sellen

Yes you can,but I doubt it will tell you a great deal until it's back with engine, clutch and gearbox united. I suppose with clear tubing you might see some air bubbles, but easy to miss. If you are doing so, put a loop in the clear tube to encourage any air bubbles to unite!

GuyW

Guy may have said this. But I'll repeat. Push the slave rod as far into the slave clylinder as it will go, and clamp/fix it there. Make sure the rear of the slave is pointing up. Then bleed. But it won't tell you anything until you have something to test it against. Engine in, then you know if bleeding has made a difference. Is your friendly club member on hand to revist when the engine is back in? Might be helpful for him to see the low bite in situ. Don't blow 250 quid until you know you really need to. If it is a seal problem, it could be the slave. Air can seep in past a weak seal. If there is even a slight moistness, not a drip, but moistness of fluid under the slave rubber dust cover, that's enough for air to get in. Sorry to say, you are back to stage one. But no matter. More than once I've gone a long way round, found nothing, and then found a simple fault, that had I found it before, would have saved me the trip. And the really good thing is, you've learned loads of very useful stuff about running/owning a Spridget. No effort is wasted. Experience is always gained. Even if it is frustrating at the time, one day, it becomes very useful.

anamnesis

I've been away for a while and only got back to this post. Read all the way through and a question. Why are you using one of Alan's excellent CRBs on a 1098 clutch? Alan has said in the past that they are only for the 1275 clutch and recommends Robin Humans CRB for 948/1098 engines. If you have used this setup since the conversion maybe the CRB face is too far away from the pad. This would explain the very low bite point. Also, as the clutch driven plate wears the pad moves toward the gearbox. Eventually, the low bite point will disappear with the result being no disengagement of the clutch. Rob

MG Moneypit

I think it's the opposite Rob. The bite point will shift higher off the floor, as the friction plate wears. Wasn't the point about the difference of release bearing heights resolved earlier, and didn't apply here? I can't find it now in this long thread, but I think it was.

anamnesis

Anstead’s roller release bearing history. Phil has one of my red 1098 roller release bearings which is quite rare. It is made with the correct 3/4” inch between spigot centre to contact face. I rarely make these like I rarely make bespoke bearings. On my Frogeye I use my own 948 bearing. There are probably about half a dozen Europe wide. Some time ago I decided to only make the 1275 roller release bearing for sale in U.K.only. Robin Human then took up the slack producing roller release bearings for 948 & 1098. I was able to have a little input with Robin’s product before fitting one of his 948 specimens to an acquaintances 948 Frogeye. Top pic: white bespoke release bearing at right.(dont recall why the stock bearing at left is also white?) Lower pic: 948 release bearing as used in my 948 Frogeye.

Alan Anstead

I was thinking a bit more about this earlier, not something I had to do much as for most of the time I had the Sprite on the road I had a cable clutch with the Ford gearbox, I had a hydraulic slave for a short while with the Ford gearbox before changing to cable. Earlier the requirement for the piston in the MC to return far enough to uncover the fluid port in the cylinder has been discussed, it doesn't need to completely return to the cover plate just far enough to uncover the hole. This allows extra fluid to enter the bore and makes up for wear in the clutch driven plate which leads to more fluid in the slave cylinder as the piston moves to compensate for the wear. I've no idea how accurate the drilling position of that hole is in the original or repro MCs, ie how much travel can exist before the clutch MC piston covers the hole. The other aspect which I'm not sure has been covered is the pedal stop in the pedal box which controls how high the pedal comes up off the floor before it hits the stop. The stop could be shortened resulting in more potential pedal travel and the pushrod lengthened so the piston is just before the fluid port, this should give the maximum fluid displacement. GuyW posted an image of his pedal box showing the MC, pedal top, stop, and pushrods, maybe Philip could do the same for comparison. Do the slave cylinders in the spridgets have a circlip to stop the piston from coming out or is that another vehicle?

David Billington

I've been following this thread with interest as I have been experiencing a similar issue with the clutch dragging. I've done or tried many of the remedies suggested but the problem persists and is worse when everything is hot. Having replaced all the hydraulics over time, I have had lingering doubts about the spigot bearing and, as I write this a fresh thought has dawned on me. Is it possible that, for both Peter's car and mine, the gearbox input shaft is not as straight as it should be resulting a misalignment in the bearing? Colin

C Mee

Colin, you've opened up a whole new can of worms! If the spigot bearing was sizing, or binding and dragging on the input shaft it could indeed cause 'creep', bypassing the clutch disengagement. And by the same score could make gear selection, particularly 1st and reverse, difficult. And if the engine has the earlier thin backplate used with a ribcase, could this extend the input shaft too far into the bearing causing it to bottom out and bind? Perhaps not the cause though, as in Phil's case the problem developed suddenly.

GuyW

The spigot could wear, and then 'suddenly' fail enough to grab on to the input shaft as you describe Guy. But of course, that has nothing to do with a low bite point at the pedal. For yours Colin, with no hydraulic issues assumed, that getting hot makes it worse, does suggest a need to look under the clutch cover, and to look at the splines on the shaft and plate, as well as inspect the spigot bearing/bush.

anamnesis

Well I am sticking to my bet on it being in need of bleeding to raise the bite point. But then casting around for a separate fault to explain the creep syndrome - either Alan's port problem or Colin's spigot.

GuyW

The pic Philip posted of his clutch fork with CRB looks different compared to the right of the 2 posted by Alan. Alan, is the rightmost CRB your special that you have made for 1098 engines? It looks like Philips is missing about 10mmto put it closer to the pad on the clutch cover. Also, Philip what is the casting number on the clutch fork you use. The 948 clutch fork is different to the 1098 item and the gearbox front plate that acts as the pivot point is different too. Maybe a mix of early gearbox front plate and 1098 clutch fork? Rob

MG Moneypit

Also, another thought. What slave are you using? 1" of 7/8". The 1" will give less throw. Rob

MG Moneypit

David. I think you meant the opposite re the fluid movement as the centre/friction plate wears. Sitting flat on a table, the pressure pad, or the fingers of a clutch cover are at maximum height. When you bolt it to a flywheel, the pressure plate draws the fingers or pad inwards. The thicker the friction/driven plate, the more the fingers or pad sink into the cover. As the friction material on the driven plate wears and thins, the fingers or pad gradually rise outwards from the cover, as the pressure plate moves closer to the flywheel. That results in the release bearing being moved back and moving the fork back *inside* the bellhousing, whilst the fork arm *outside* pivots towards the slave cylinder, pushing the slave rod farther into the bore, and the piston then forcing fluid back up the line and back into the master cylinder. I'm pretty sure that's right.

anamnesis

David B: I’m away from home so not in a position to post a picture. Yes I saw Guy’s image of the pedal stops, and they look different to mine but then, because you can adjust the pushrod on its threads, you can have different positions/appearances of the set up that result in the same amount of travel. Guy put a disclaimer on his image I think probably for this reason. I’m experiencing the same symptoms whether the car is hot or cold, so a little different than yours Colin. With respect to the gearbox shaft/bearing alignment, the individual I was discussing this with yesterday looked at the arc travelled by the fork over the shaft and didn’t identify any discrepancies. Sorry if this doesn’t help you Colin.

Philip Sellen

Anam, Well spotted, it was some time after the edit window had passed and I thought 'boll**ks' that's wrong. I had the BMC and Triumph slave positions mixed in my head and realised it wouldn't work as I had it in my head. Quite correct the that as the driven plate wears extra fluid is forced from the slave cylinder back to the reservior.

David Billington

Easily done David. More than a few times I've realised my mix up, and raced to correct my mistake, before edit time out, and before someone else spots it and does. I think in this thread or another just the other day, I missed the edit time, but got my correction in, in the next post, before anyone commented. Phew. Lol. Stressful this bbs forum malarky, innit. 😅😅. Glad it's not fb, where you have to worry about 'likes' and whatever other flags people can chuck at you. Lol.

anamnesis

Guy, "-- either Alan's port -" or " - Colin's spigot." How about novacula Occami? 😉

anamnesis

😁 had to look that one up Anam. Still not sure I understand 😂 Maybe go for "any port in a storm" as appropriate guidance

GuyW

Latin for Ockham’s razor. I was just joking really, to go alongside your Alan's and Colin's. But, https://the-philosophers-shirt.com/en-gb/blogs/philosophical-dictionary/occams-razor-and-the-common-sense

anamnesis

M.G.Moneypit Phil has the correct red roller bearing for a 1098: 3/4” centre of spigot to contact face.

Alan Anstead

Philip--you'll be wishing you didn't mention your issue before long-- But with all the posts suggesting wrong parts etc. we need to remember your car was fine and working properly and then something has changed while out on a single drive. I doubt it's the spigot bush, i've had them fail and you just can't get into gear and very difficult to separate the engine from the gearbox--and doesn't effect pedal height. Check it by all means but i doubt it's an issue here.

William Revit

Alan: Thanks for your earlier explanation on your product range. Anam: Yes, I’m aware that if I bleed the SC before the engine goes back I’ll not be able to verify anything until it’s put to use, but it’ll be easier to bleed - which can’t be a bad thing. As and when I need to remove the MC, I’ll dismantle it first to see if it just needs a repair kit rather than a full re-sleeving. As the cost saving would be significant. Yes, thanks Willy.

Philip Sellen

If you do bleed the SC now, although you won't be able to test if it's worked, hopefully you will notice any air that may be bled from the system.

Dave O'Neill 2

Yes exactly Dave, so probably worth doing.

Philip Sellen

So everything seems OK parts wise, so I went back to the start and read Philips first post. That triggered a memory from 2018 I think. Driving from Angouleme with a few NW guys we decided to stop at a roadside restaurant about 1/2 way to our hotel at the midpoint of our journey back. Everything 100% till then. Had a nice lunch, departed the car park went 110 mtrs or so and the lead car pulled into a layby to let the stragglers catch up. I de-clutched but for some reason kept going and just missed running into the car in front. From that point on the clutch wouldn't de-clutch. I had to do 5 or 6 rapid pumps on the clutch pedal to be able to get into first gear. That was an entertaining journey back but we managed to get back home. That turned out to be the clutch master cylinder rubbers. Well that was the last thing I changed to get it back to normal after going through everything from the SC back to the MC. Karl Thompson mentioned the same thing as well, and the pic from the MGA Guru website was the same. Maybe it is just that the MC rubbers need changing? Rob

MG Moneypit

Rob, I’m heading in that direction.

Philip Sellen

Philip. I've changed my mind. You **can** test after bleeding, before putting the engine back in. And it may possibly show up a fault in the master cylinder. Press the slave rod as far into the slave cylinder as you can, to force the piston back as far as it can go, and clamp it there firmly. Bleed it. With the slave piston still locked in hard by the rod, you should now have a very firm/hard pedal, that won't depress much at all. Press *hard* on the pedal, and keep up the pressure. Be patient. It may take a while to give the following result. Keep up the foot on pedal pressure. If the master seals are faulty, the pedal will gradually sink to the floor. The worse the seals are, the faster/easier the pedal will sink to the floor, as the fluid seeps past the seal. And that will match Alan's description earlier in the thread. "A rubber in the master cylinder was pushing the fluid forward, to disengage the clutch, but then letting it past -". If that happens, you have your answer. BUT, you may say. When I tested before pulling the engine, the rod didn't sink back into the slave. BUT I say. That could be because the clutch cover springs weren't exerting enough back pressure to reveal the MC seal problem. Whereas, a locked in slave piston, and your foot hard on the pedal, will exert more pressure on the MC seals.

anamnesis

Thanks !! Having got oil pressure and got it running, then found a rusty slave cylinder that hid the fact a muppet ( me ) had fitted the F**k***g clutch plate the wrong way and I still don't have gears !

Malc Gilliver

Alan Anstead Where can I get one of those 'real' thrust bearings for my 1098 Sprite that replace the silly carbon ring ? Thanks, Malc

Malc Gilliver

Malc For a 1098 you will have to get a release bearing from Robin Human whom you will find on Fb. Alan

Alan Anstead

Thanks Alan, I'm not on FB, any other options ?

Malc Gilliver

Malc Intelligentmetals at gmail dot com

Alan Anstead

Thanks, Emails sent !

Malc Gilliver

Update. A number of commitments has slowed my progress in chasing down the clutch problem. However I can report that I’ve now removed, cleaned and fitted a service kit to the SC. The cylinder bore was dry with little black smudge like deposit - no doubt wear from the internal seal, so nothing obvious. This is now ready to go back, with a home made remote bleeder attached. The MC has also been removed, dismantled, cleaned and is nearly ready for reassembly with a repair service kit. Again, nothing obviously wrong when I opened it up. And again there was some black debris that came out with the internal components, mostly on the clutch side. There was, as expected, wear on the internal seals, a visible difference compared to the new ones. I can only conclude at the moment that in renewing the components will return the clutch to normal function, but it’s going to be a case of wait and see, as there’s no smoking gun to tell me anything else. I intend to bleed the cylinders prior to engine/box installation as I think I’ll have better access to jiggle the SC in order to eliminate any air. I also think I’ll need to pay particular attention to the pedal clearance set up to ensure this is correct. Gratuitous image attached for interest only really.

Philip Sellen

Stating the obvious here, but when bleeding the slave before installation you will need to clamp the piston to stop it simply popping out of the cylinder. You may as well do what Anam and I have been saying, which is to push the piston as far back into the cylinder as you can, and clamp it there. The reason is because otherwise there is a strong possibility that air will remain in the cylinder as the bleeding process simply pumps fluid in at the back of the cylinder and straight out of the adjacent bleed nipple (in your case now via the extended bleed pipe)

GuyW

I may have mentioned it before but a local guy had no end of trouble bleeding the slave cylinder on his Fiat X1/9 when he replaced the original with an aftermarket one, he tried all sorts of bleeding procedures and tools and none worked as no fluid could be forced into the slave. In the end he disassembled the new cylinder and found the problem, the original had a step internally which stopped the piston reaching the end and blocking the fluid port and bleed hole, the new one didn't have a step so when the piston was fully in it blocked fluid entering the cylinder and being bled. He pulled it back a bit to unblock the port and all was good.

David Billington

Yes thanks Guy, I did have that in mind. Hopefully it’ll bleed easily without the hassle that can sometimes accompany this exercise.

Philip Sellen

Thanks David, I presume that situation is not possible with the Midget because of the internal spring but it’s interesting to hear about it.

Philip Sellen

Goodrdge Speedbleeder - It appears that Goodridge sell a bleed nipple with a ball and spring inside to allow for one person brake/clutch bleeding has anyone tried one of these things ? https://www.youtube.com/watch?v=fMT9TE6vFvA It appears Russell make them aswell

Malc Gilliver

I’m fitting one to the SC, but haven’t got as far as using it yet.

Philip Sellen

Used those many years ago on my minis. No idea of brand or supplier. I am talking about the 1960's ! But I do remember they worked well.

GuyW

Me too Guy. But the closing valve was external. Used the on my Sprite. Which is odd, because as you say, they work well, and yet I don't remember why I'm not using them now or where they are?

anamnesis

Anam, Guy and Philip. Thanks guy's glad to know they work, I'll be treating the Sprite SC to one of them and a flexi braided feed hose, I was going to fit a remote but was never keen on having all extra plumbing.

Malc Gilliver

I am using Goodridge ABVs on my cars. As some have said “nothing new” but I think the 60’s editions fell from favour as the internal springs rusted whereas today, hopefully, they are stainless. I thoroughly recommend a remote bleed with or without ABVs. It makes the bleed valve so accessible. I have added a handle to my exhibition demonstration bell-housing to make carrying more easy. Don’t ya hate it when the pics load sideways. Why does it do that?

Alan Anstead

Alan, Thanks I can see how that would make life easier. I can see PME do a remote hose for the 1275cc SC but not the 1098cc SC.

Malc Gilliver

I dont think much of the PME remote. The simple method, which suits all engine sizes, is to use a Spridget rear brake hose either stock or reinforced. Of course you can just use brake pipe in its various forms. Attach it to a Spridget rear brake 3-way union: just blank off the 3rd inlet / outlet port. The 3-way has a 1/4” hole to attach to a bracket that will need to be made: B & Q supply strip steel suitable for making brackets. Attach the bracket as per my demo on the top bell-housing bolts. Use copper washers, where appropriate to seal the joints.

Alan Anstead

A good deal cheaper too, done as Alan describes, using the standard rear brake hose etc rather than the PME offering. Definitely worth doing, either way.

GuyW

ABV's. Them's the ones. You can buy original NOS ABV's on Ebay, -- if feeling nostalgic 😀.. https://www.ebay.co.uk/itm/127122231042 And you jogged my memory Alan. Rusty springs. That's why I haven't got them any more. If they have stainless steel springs now, maybe I'll invest in a set of the new Goodridge. But maybe not, since the wife's foot is free, and freely available on demand. 🤣🤣🤣. Yep, gravity assisted automatic remote self bleeding on the clutch. A fortuitous consequence of using an internal concentric clutch slave, -- easily added to the original external slave. Bits of pipe and a nipple bolted to the bell housing. For simplicity, economy, and above all efficiency, why spend more? Here's an earlier thread discussing it, way back in september 2011. --- "I well remember the same problem after replacing the clutch slave. Grotty job bleeding the thing. Then I changed to a 5 speed box. The 5 speed g/box conversion I have, also included a relocated slave cylinder bleed nipple. It now sits on the top side of the g/box, just below the battery shelf (drivers side, rh drive car). It is EASILY reached from inside the engine bay. Why not fit a length of pipe to the end of the slave in place of the existing nipple, and locate the nipple at the end of the pipe, which can be at the top side of the box, or if flexible, anywhere you like? This would allow you to bleed the slave with ease. I remember thinking I should have thought of this myself long before I installed a 5 speed box." http://www.mg-cars.net/mg-midget-sprite-technical-bbs/how-do-i-bleed-the-clutch-on-my-mk3-midget-201109032104176702.htm

anamnesis

I have made quite a few of ABVs over the years for a number of specialist vehicles where 1/4" or larger thread sizes (BSF/UNF/Metric) are applicable but use a simplified version for smaller sizes where only a stainless steel ball but with no spring is used. All ABVs are subject to pressure and leak testing at 2000psi. Cylinder ports need to be carefully cleaned to ensure a suitable seating essentially meaning off vehicle working to ensure that no debris is able to enter the hydraulic system. Attached photographs show typical nipples and range of seating and port cleaning tools.

S G KEIL

S G Kiel, They look more secure than the ones with a hole in, you have release the speedbleeders and then the bleeder comes of the seat, whereas with yours they stay seated until fluid pressure lifts the seal.

Malc Gilliver

Apologies for the delay in getting back to you with my investigations into the clutch problems. Unfortunately car mechanics have been unavoidably delayed due to a string of prior engagements over the past few weeks which have hindered progress in getting the car back together. I’m now finishing the last few tasks in setting the car up for an engine off check of the MC: brakes then clutch (hopefully no more bleeding required). Having reassembled with new seals and installed the pedal box - being careful to preserve the pushrod and forks as they were, I noticed the slave pushrod sat at a slightly different length than before, relative to the pedal stop adjustment bolt. This suggests to me this is indicative of the worn out seals I removed from the MC, and hopefully will result in a properly working clutch pedal. I’ll let you know what happens when I get to operate the MC with the engineer running, which hopefully will be quite soon.

Philip Sellen

As I approached completion of engine/ancillaries installation, I became less and less confident that the problem might be resolved. Bled the MC clutch and brake systems - this seemed to go too well, as both pedals appeared firm and hold pressure. Slave piston travel is as it was originally. So with everything back in place, I started the engine for the first time in nearly 3 months (nearly first crank of the engine) I've taken it for a spin literally up the road and back for 2 minutes to see what it's like in a few gear changes. I can report that the car now appears to be back to normal with respect to clutch/gear changes - and it looks like the weather has remained warm and dry to give it a more substantial shakedown drive in the next few days. Without reading back through all the posts, I think the cigar goes to Karl for suggesting it would be the MC seals. However, it was useful to remove the engine as I picked up on a few minor maintenance points that I would otherwise have missed; an exhaust bracket rubber had perished and was just hanging on and, more seriously, the LH steering rack bracket had fractured. Not visible or evident until the radiator had been removed. Many thanks to everyone for taking the time to respond to my call for help, and all your suggestions. I still cannot resolve how I ended up with the symptoms of a pedal that would hold pressure but reduce the gear engagement to a semi-dangerous state.

Philip Sellen

Glad you've got it sorted and can enjoy the car once again. That type of fault can be so annoying/frustrating.

Jeremy MkIII

Glad it's fixed Philip. Enjoy the weather this week 😎.

Bill B

"Slave piston travel is as it was originally. " I'd say not. It's clearly moving more. " -- I still cannot resolve how I ended up with the symptoms of a pedal that would hold pressure but reduce the gear engagement --" I'd say you have the answer. The slave rod simply cannot have been moving the fork and hence the release bearing sufficiently, to disengage the clutch sufficiently, to allow the input shaft to stop turning as you tried to engage gears. And that's because your master cylinder seals were likely knackered, as previously described first I think by Alan, in the 4th post of this thread. All good educational fun and useful experience gained by you. 👍🙂

anamnesis

This thread was discussed between 22/05/2025 and 10/08/2025

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