MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Shock and bushes decisions

Following the excellent advice on this board and a morning spent combing through the archives (wow!) I am nearly ready to upgrade the shocker bushes to PU units, at least. A few final decisions need to be made on which I should like your input.

1) At least one person has in the past upgraded bushes without lowering the suspension. Lowering knuckles do not seem within my DIY ability and I am not sure I want to lower the standard height, either for aesthetics or fun. My guess is that the change to PU bushes is worthwhile anyway...any views?

2) Caffyns say they have changed very few dampers and only if broken. Even at the £200 plus mark for AVOs, these are more than I would like to spend at the moment. But if I have to undo it all again...on the other hand having done it once, everything should be loosened up nicely. Although finances may make this just a no go, am I being foolish not changing the shocks at the same time?

3) Knowing how easily I make a mess of nuts, I was thinking of ordering new nuts, bolts etc for putting it all back together. One lone voice in a thread mentioned uprating the bolt at the bottom of the shocker using Roversport parts, since the uprated damper would otherwise bend it. Any comment?

4) I may as well do the rear tie-bar bushes at the same time since this is the other easy, handling related PU bush. Judging from the archives, for a road car without a F1 driver in charge, keeping the standard tracking or slightly closer to (but not at) parallel is the best choice... ie: allows more accurate turn-in but without encouraging too much oversteer.

Thanks all....

Chaz
C Golvala

Further diligent reading of Rob's suspension pages (thanks) means that point (4) above is answered. Recommendation is keep the rear setting as they are to protect against oversteer, even with compliance washers and possibly straighten the front to improve turn in but at the cost of steering feel.

Assuming worn tie-bar bushes and therefore worse toe angle changes than were designed for, what would the suspension do in a corner? Presumably, more of what it was designed to do, causing greater understeer? Would this reduce grip as a result of changing slip-angles? I have not read the new(ish) slip-angle pages, so am still at the pre-nursery-school stage on that subject!

Any views on the first three questions still welcome.

Thanks

Chaz
C Golvala

Two more questions in case anyone is watching me make a fool of myself...!

There is a spacer and two washers on the bolt that goes through the bottom of the damper (very clearly seen on "aptony"'s site). Might I need to replace these when fitting the PU bushes on a 7 year old?

Anyone know the size/thread etc for the not at the top of the damper? I'm sure to need a new one once I'm done and Caffyns say that it is not listed on their system.

Cheers

Chaz
C Golvala

Rob is probably the best person to answer this (i could have a go, but i will probably get a few things wrong!) ;-)

You out there Rob?

SF
Scarlet Fever

The PU bush kit from Mike Satur I believe if I remeber correctly comes with new spacers.

I have fitted the bushes, but have to warn you it is not quite as easy as you may at first think. Access to the lock nuts on the rear dampers in the engine bay is not easy. I had to resort to getting a friend around with an air wrench to spin them off.

They are a worthwhile mod, I could feel the difference on my car which is 7 years old and has done 38000 miles (the original dampers were retained after a coat of paint).
Dave

Just out of curiosity, why do you feel you need to upgrade the shocker bushes? If it's handling related, are you sure other items are within spec?
L Reid

Well, this weekend I bought a lot of kit that I needed (new socket set, new torque wrench, penetrating lubricant, 14mm rachet spanner as recommended by TW's instruction) and then had no time on Sunday to do the job. Next weekend, I promise!

I decided to do the bushes for several reasons. First is that they clearly need doing in any event. Second is that as far as I can tell the other obvious handling factors are OK (tracking, tyres, pressures, ride height, hydragas, bearings etc). Third is that a trawl through the archives shows other people solving similar handling issues through this mod. Fourth is that it is a cheaper first step than replacing the dampers. Fifth, I think I can actually do this whereas other investigation or work I'd have to pay for. Last, that the rear tie bar bush may also contribute to the problem and I might as well order the shocker bushes at the same time (and vice versa).

Something like that anyhow...

Chaz
C Golvala

Hi Chaz,

I'm a bit late to this thread - been away, enjoying a bit of R&R :o)

>>1) At least one person has in the past upgraded bushes without lowering the suspension. Lowering knuckles do not seem within my DIY ability and I am not sure I want to lower the standard height, either for aesthetics or fun. My guess is that the change to PU bushes is worthwhile anyway...any views?<<

Firstly, assuming that we are talking just about the damper bushes, then yes, they are well worth replacing. The standard items are soft and wear prematurely.

Secondly, assuming that we're talking about wholesale suspension bush replacement here, whether PU bushes are worth while is dependent upon how you intend to use the car, and how long you intend to keep it. The advantages of PU bushes are much better suspension geometry control - PU bushes are much less compliant, and therefore have less 'passive' movement with cornering forces etc. The downside is that more noise and vibration are transimitted into the cabin. They are also a little more costly to fit than rubber bushes.
So the question you need to ask yourself is - "are they worth fitting on my car?"
Personally, I think that the answer is yes, but then I'm more than happy to accept the less desirable consequences. Andy G is very happy with his car with PU bushes - and a quick blast around the block showed that ride comfort wasn't really too badly effected - so these PU bushes don't seem to be too much of a compromise.

>>2) Caffyns say they have changed very few dampers and only if broken. Even at the £200 plus mark for AVOs, these are more than I would like to spend at the moment. But if I have to undo it all again...on the other hand having done it once, everything should be loosened up nicely. Although finances may make this just a no go, am I being foolish not changing the shocks at the same time?<<

Dampers are well worth fitting. The reason for this is that the standard dampers only provide resistance on extension, and offer almost none on compression (even those fitted to Trophy 160s). You'll notice quite a dramatic difference with new dampers. However, these can be fitted at almost any time (they're not too difficult to remove, as Tim will tell you).
I haven't tried AVOs - but in the world of dampers, the more expensive makes of dampers are more expensive for good reason: quality.

>>3) Knowing how easily I make a mess of nuts, I was thinking of ordering new nuts, bolts etc for putting it all back together. One lone voice in a thread mentioned uprating the bolt at the bottom of the shocker using Roversport parts, since the uprated damper would otherwise bend it. Any comment?<<

New nuts and bolts should not be necessary. They're pretty sturdy - and besides, replacements should be readily available cheaply from your local MGR parts department :o) Can't comment on the lower shock mounting bolt, as this is not a problem I've personally encountered.

>>4) I may as well do the rear tie-bar bushes at the same time since this is the other easy, handling related PU bush. Judging from the archives, for a road car without a F1 driver in charge, keeping the standard tracking or slightly closer to (but not at) parallel is the best choice... ie: allows more accurate turn-in but without encouraging too much oversteer.<<

These are worth doing. The built in passive rear steer is fine under certain circumstances, but too much, especially under conditions of braking, can lead to the rear of the car becoming unstable.
IMO, Malcolm Gammons is quite right - these are items that are well worth obtaining - even if you only get the 5 quid spacers.

Hope this helps :o)
Rob Bell

> replacements should be readily available cheaply from your local MGR parts department

Don't be so sure. I was quoted 3-6 days wait for a 59p Caliper mounting bolt when replacing discs on my 'F', and the same wait on brake disc screws (which are only available in packs of 10 apparently).

Leigh
Leigh

Rob, thanks for chipping in. I have the damper bushes now but ran out of time on the weekend. I'm only going to try the damper and rear tie-bar bushes, since these should be within my DIY ability. If that doesn't sort out the handling then I will have to consider new dampers and other investigations and solutions. I suspect that the rear tie-bar will make most difference to the drive through corners on poor surfaces and when braking, but the better located dampers should help general road-holding. Any views on the rear tie-bar thread?

Leigh - I have had the same experience with MGR. The spare nuts (Rob, if I don't knacker at least 2 out of four, I'll be surprised) washers etc are on order from the factory and theoretically will take 3 days to arrive. They don't have a part number for the nut at the top of the dampers so can't supply that! I noticed brake disc screws (4) in the B&G or Moss catalogues however.

Part way through writing this, I got a call from Techspeed in answer to my email. They made the same point that Rob does and I'd love to do their conversion, but £600 I do not have. The guy I spoke to said I should try Rob's car...a bit free of him, I thought :-)

Chaz
C Golvala

>>The guy I spoke to said I should try Rob's car...a bit free of him, I thought :-)<<

ROFL

You're welcome to have a go Chaz :o)

Dampers are worth considering - they really do transform the car. As you know, I went down the TS route, and am absolutely delighted :o)
I confess though, the cost did cause me to baulk over the idea of the conversion for a number of months. However, after having had the Bilsteins fitted, I thought "what a bargain!" It's that kind of transformation.

You are probably approaching this from a different angle to the one I took regarding damper change. You are seeking to correct a pre-existing handling problem. From experience, and from what others have told me, Techspeed have the skills to sort your handling problems out for you. Perhaps more expense - and perhaps even slightly less self satisfaction for solving the problem yourself, but money well invested in terms of hastle reduction! :o)

And if you go for their suspension upgrade, well okay, your bank manager won't be smiling, but I can pretty much guarantee that you will!!! LOL

PS I don't work for them!
Rob Bell

Chaz

If you want a ride in a F with the Techspeed suspension and polybushes all round give me a shout, I'm not that far from town..

The ride is definately harder but the handling and cornering is excellent...

Stu
Wokingham
S.C. Dickens

This thread was discussed between 02/04/2003 and 07/04/2003

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now