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MG TD TF 1500 - 1. gear has another clutch effective movement

I'm converting the clutch pedal from cable to rod. When I got the car it was very difficult to switch into the 1th gear. The effective movement of the 1th gear was less than the other gears. I'd learned to balance clutch and throttle, but it was always an effort.

First test with the rod shows that it now seems impossible to switch the 1th gear in a smooth way. The clutch has so much bite - but only in the 1th gear. The car makes a bounce and the engine dies. Workaround is to start in 2nd gear. Any ideas?

The lever on the gearbox can be moved very easy. Next step is to activate the O'Connor modification. But why is the 1th gear so much different?


Bela

Bela,
Does the same "Bite" occur when you try reverse?? Is it like a Chatter??

Steve
Steve Wincze

Bela,
Before you go and modify the linkage,,, do the easy check first,, and that is check the rear axle "U" bolts for tightness. It could be a possibility that they are loose, which causes the axle to "wind up" in first or reverse,, This is because of the low gearing in first and reverse,,
This was the condition of my TD, and tightening the "U" bolts solved the problem.

Hope this helps,
Steve
Steve Wincze

Thanks Steve

I will check it. The "reverse" gear doesn't show the same effect as 1st gear.There is no chatter in reverse. To notice a remarkable chatter in 1st the time is to short but it is loud and hurts me.
Bela

bela,
How old is your clutch?? Are there a lot of miles on it??

Steve
Steve Wincze

After checking rear bolts as Steve suggests, check all of the engine mounts- the front one and stabilizer bar assembly and bracket to the frame. The rear transmission mount steel box around the rubbers often fractures at the side ears. George
George Butz

Bela - Before doing the O'Connor modification, read the article, Clutch stop in pedal box in Bud Kruger's Ttalk http://www.ttalk.info/Tech/TechIndex.html You might also want to look into Declan Burn's improved clutch rods - contact him at: declan_burns@web.de Cheers - Dave
DW DuBois

I can't say how old the clutch is or how many miles the car drove. I have some documents but the mileage isn't traceable because the speedometer had been changed. Last engine overhauling was 1980. The pre owner would not or could not say the real count. Generally the clutch and the gearbox work fine - no slipping and no scratching. Only starting in 1th gear makes the described trouble.

I'll check all the mentioned point at next weekend.




Bela

Hi Dave,

I have read the articles and I have some of the parts from Declan installed - but until now without the O'Connor modification. At this point of my work I recognize the different and bad behavior of the 1th gear. Declan has drilled the hole into the lever and made some bearings. With RHD there is only little space for all because Declan's part are a little bit out of the original straight line. I'll install the stop bolt too. Stepping on the clutch pedal is very soft. I'm waiting for a new return spring too.

The hints are very helpful. I can imagine that an additional movement of engine/gearbox effects an deviation of the rod. The cable may be more tolerant against such a movement.
Bela

Sounds like you have been "feathering the clutch" which in conjunction with the dampening action of the cable linkage may have been hiding other issues. I believe you may have to go back to basics and check all the drive train components, mountings, play in the pedal box and clutch rod bushings. If all those components are sound the clutch internals may be next project.
G Evans

In my Td, the rear transmission mount was wobbly (rubber pieces gone). The clutch lever modification and fixing the mount both gave a noticable improvement.
My guess is that you notice the bevaviour in 1st gear because the gear ratio is so much higher than in 2nd which pronounces all the above effects. I had the same feeling before the mods. Clutch was still a bit sharp after all the changes, though.
Now with the changed diff ratio, all is fine.
Rgds, Mike
Mike Fritsch

I'd studied the workshop manual and found:

"If any difficulty is experienced in freeing the clutch when the correct release movement is provided, on no account should efforts be made to improve matters by attempting to increase the effective pedal travel."

I’ve also read the article about the O’Connor modification.

Doesn't the intervention with the O'Connor solution leads to an increment of the effective pedal travel too? If yes – what’s about the position of the stop bolt?

I don’t want to discredit the O’Connor modification – I only want to understand.
Bela

The O'Connor modification gives more pedal movement for the same clutch action. This makes for more control.
Dave H
Dave Hill

The O'Connor modification gives more pedal movement for the same clutch action. This makes formore control.
Dave H
Dave Hill

I've got it. According to this fact - must the given travel way of the clutch pedal, limited by the stop bolt, then be increased (new place of the stop bolt)?
Bela

I didn't fit it. Its not needed with an adjustable clutch rod, correctly set up.
Dave H
Dave Hill

Hmmm...if you shorten the effective arm and move that point the same radial distance..don't you get more clutch action with less pedal travel?
Regards, tom
tm peterson

Tom

You are correct, peoples terminology is creating some confusion.

There is the need to study the O'Connor diagram contained in http://www.ttalk.info/Tech/TechIndex.htm. Adjustment of rod/rods length must center the clutch lever.

I found I had to remove the stop bolt to meet this criterion. Whether or not the complication that I have a TC gearbox and its associated modifications to mounts in my TF has had some affect on the geometry is unknown.
G Evans

Hi Dave,

I'm a newby and I'd never had done before. If you say correctly set up - what is the procedure?

The workshop manual says 19mm free way measured at the pedal. It also says there should be an approximately 29mm clearance between the stop nut and the abutment bracket when the pedal is lightly held with the carbon block in contact with the thrust ring by pushing lightly on the clutch pedal by hand. Absence of the cable doesn't change this distances. Is it this what you mean?

@Tom
What I'd understood:

It is necessary to operate the clutch between pressured mode and free mode. If I'm right the distance therefore at the clutch is 7,9mm and additional 1,59 mm minimum clearance for the free movement of 19mm at the pedal.

Proceeding from this the way of the pedal depends on different levers. There are 3 - gearbox, sump side and clutch pedal. The O'Connor modification makes a change to the lever at the sump side only.
It shortens the effective arm. Due to that, the point on the shorter radial distance must travel more and the end of the rod from the pedal must also travel more. So you get more pedal travel. But if you have more pedal travel - isn't it necessary to find a new position for the stop bolt?

I don't have the bolt. I've seen a picture with a welded bolt and a drawing with a slot for the bolt. Anyway - I have to find the correct position and I think that depends on the presence of the O'Connor modification. Am I right or is it only an academic discussion without practical relevance?
Bela

Hi Bela,
Figure E2 in the workshop manual shows the relative angles of the rods, it is a drawing of the cable type but shows the correct position of the levers
The rod between the bellhousing lever and the lever on the sump must be adjusted until those angles are correct ( that is on cars so fitted). Then and only then the pull rod between the clutch pedal and the sump lever can be adjusted.
If you are using the O'Connor method then you do not need the pedal stop, if original position then you do need it. With no stop the clutch thrust will drive into the internal levers of the clutch pressure plate and be damaged.
I just had to help a Y Type owner who did just that.
I have also found that too strong a throttle return spring an cause a judder on take off.
Ray TF 2884
Ray Lee raybar2(at) tiscalidotcodotuk

Hi Ray,

then I can start with the approximate angles (no measurement :-( ) in Figure E.2.

What is the reason for the absence of the stop bolt in case of O'Connor?
Bela

Hi Bela.
with the O'Connor modification the push rod movement is reduced as the new hole is closer to the pivot. This means it does not travel enough to foul the pressure plate.
Ray TF 2884
Ray Lee raybar2(at) tiscalidotcodotuk

Ray has it absolutely correct.
Dave
H
Dave Hill

Thanks all

for me it's like valerian not to drill the hole or slot for the stop bolt. But I'll keep an eye on it ;-).

Additional question:

What may the correct torque for the u-bolts?
Bela

An overly sensitive clutch, especially if it jerks when going into a low gear, can be caused by the gearbox output shaft, the driveshaft, and the differential being out of line. If the gearbox or differential are not level with one another, the clutch can be "fierce" and result in difficulty shifting smoothly.
Lew3

I've seen in a drawing that the flywheel housing has an inspection hole. Can it be used for adjusting the clutch?
Bela

Hi @ all

Today we have done our exercise and the clutch is working nearly as before. We had a short ride only but it seems okay.

The U-Bolts have been loose and that was responsible for the difficulties with the 1. gear.

Thanks for all the useful hints.

Special thank goes to Declan Burns with his improved solution for the clutch rod and his additional efforts with some special parts for the RHD TD, which didn't want to give the required room beside the pipe.
Bela

This thread was discussed between 17/03/2016 and 26/03/2016

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