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MG MGA - Clutch pressure plate

Hi all,

I have just pulled the engine out of the car. This I did to be able to get the gearbox out to replace the synchros and anything else that may be in need of renewal. Because the clutch used to judder a bit on first & reverse, I stripped the clutch to examine all parts and all I could see were the following: The clutch driven plate looks OK except that the side nearest the flywheel was somewhat glazed. The pressure plate side is perfect. The pressure plate has a smooth surface which looks OK to me, but the concentric setting seems to be off not dead parallel as it should be. The flywheel face is badly groved. Up to this point I have already decided to replace the driven plate for a new one, re-surface the flywheel at an engineering firm and put in a new release bearing. Is it a finicky job to adjust the fingers on the pressure plate? I do not have a dial gauge. I am trying to avoid buying a new complete pressure plate, because to have one shipped to Malta would most probably cost a small fortune. Any suggestions and/or advice will be most helpful.

Frank
F Camilleri

Frank

I had the juddering and also found off centre marks on the thrust ring. This all turned out to be a worn bush in the clutch operating arm, allowing lateral movement of the arm. A new bush cured the juddering.

Steve


Steve Gyles

Steve

Yes I know exactly what you mean. I haven't pulled the gearbox out yet, but I will most definately replace that bush whatever state it's in, and most likely the pivot bolt too. However, I was refering to the pressure plate when I said that it is not concentric. This is adjustable but I believe to be able to do precise measureing and adjusting of the fingers, one needs to use a dial gauge. Unfortunately the one I have is unserviceable. For their price I'm not sure buying a new is the right thing to do when you consider that I won't have much use you for it after fixing the clutch. Of course, I would prefer to replace the whole pressure plate setup, but I have a great disadvantage of having to buy all parts from UK, and in doing so, incur high shipping costs. I found a new clutch plate locally, but a new pressure plate is not available anywhere.

Frank

F Camilleri

Frank,

The terms you use are a bit confusing. You use concentric and parallel in the same sentence.
Which is it? Or both?
I think that you mean that the pressure plate surface is not parallel to the flywheel surface. But how do you know this? You say that you do not have the equipment to measure it. You cannot tell from wear marks as every time the clutch is used a different section of the clutch disc comes into contact with the pressure plate and the flywheel.
I would have thought that there would be many older British cars in Malta. Surely there is a workshop with the proper Borg & Beck jig, as shown in the Workshop Manual?

Mick
M F Anderson

Mick,

Sorry to have caused confusion. What I really meant was that the pressure plate face does not seem to be parallel with the flywheel face. This is quoting the w/shop manual. Putting the clutch disc onto the pressure plate face, and using a straight edge, I measured the gap between the face of the disc and the flat portions on the outer circumference of the cover, where the bolt holes are. I used feeler gauges to do my measureing. Not a very accurate way of doing it, but I believe it gave me an idea. This is where the dial gauge is a must for proper adjustment of the fingers. Yes Mick there are hundreds of British cars in Malta, the majority of which are very well looked after classics, but I very much doubt there will be a shop equipped with a Borg & Beck gig. Nonetheless, I will ask around. Thanks Mick.

Frank
F Camilleri

Frank,i canot see how this idea of yours, of using a clock gauge to set the cover fingers can work,what do you use as a reference point,yes you can set all the fingers to the same hight, but how do you know what that is,i have adjusted dozens of covers but only with the special cover adjustment kit,which only took 5 mins from start to finish,i am not saying you can not do it, but i can not see how you can do it correctly, and if you adjust it wrongly, its a lot of work to put it right, which means using the correct kit, or a new cover, Best of luck, A.T
andy tilney

Frank

Why not fit an MGB clutch assembly. It is a better unit, lighter, cheaper and probably more readily available in Malta.

Barney tells you how to do it: http://mgaguru.com/mgtech/clutch/ct_102.htm

Cheers

Steve
Steve Gyles

Frank... Ill be hitting the MGOC soon ..

ley me know if you need anything, I can deliver to Charles friend in Central London...or post direct..
Sorry no plans to be in Malta soon ...that drink will have to wait...

ken
k klay

Frank,

You cannot measure the parellelism of the pressure plate by using the clutch disc as a reference.
The clutch disc can be irregular in the surface wear and could be slightly buckled.
I support Steve's idea of a MGB clutch, but if there is not a workshop anywhere in Malta with a Borg & Beck clutch jig I would have to assume that there would not be a machine shop that could drill the three holes in the flywheel to the precision required.
Any error there and you will have a clutch that is not concentric with the driven parts.

Mick
M F Anderson

Thank you all for your interesting comments and advice, all were very useful to me. I have now decided to buy a new complete clutch kit which will eliminate my pressure plate problem. Ken, thanks for your kind offer, I will send you an email today. Please let me have your reply as soon as you can. I have a cheque for you but don't know where to send it. We will talk about that via email. Many thanks to all.
F Camilleri

Pressure plate problem solved. Bought a brand new original equipment complete pressure plate locally. Very cheap, one third the price as listed by UK suppliers.

Frank
F Camilleri

Fank

MGA or MGB?

Steve
Steve Gyles

Steve,

It's an MGA original Borg & Beck. I don't see the point in updateing to an MGB clutch with all the modification that goes with it. I thought I'll stick to the original. After all I do very little driving with this car, and I try to keep it as orignal as I possible can.
Steve where can I buy a couple of camshaft offset keys with a 3 degrees offset?

Frank
F Camilleri

Frank

Not my area of knowledge. Let others chip in on that one.

Fully appreciate your stayng with the MGA clutch. That said, I put the MGB version into my 1800/5 speed conversion 10 years ago. Much smoother operation and judder free (provided the operating arm bush is ok).

Steve

PS. Spent a very enjoyable month flying Lightnings out of Malta back in 1970. Bet it has changed a lot since then.
Steve Gyles

Steve,

I think I'll be quite happy with the original MGA clutch. I did have some judder on first & reverse gears, but now I know why. The flywheel is badly scored the pressure plate was out of true, the cluth plate was glazed on the flywheel side and the bushing of the operating arm are badly worn. Even the release bearing is unevenly worn. No wonder the clutch juddered. I will replace all these items, except the flywheel which I will have re-faced at a local machine shop.
Yep, I do remember the lightnings from when I was stationed at RAF Luqa(10years). They were extremely fast, as you will of course know, and also extremely noisy. I used to love watching their afterburners at night when I was on duty. It's all changed now. No more military bases here now. But overall the island has changed a lot for the better. I worked ground to air comms with RAF transport aircraft, shackeltons and nimrods mainly. Where you stationed at Luqa or just on visits?

Frank
F Camilleri

Frank

It was October 1970. We operated out of the main base but lived at Luqa.

We were trying to demonstrate that the RAF could operate air defence in the Med without aircraft carriers. It was at the time the previous HMS Ark Royal was being decommissioned - what goes around comes around!

Steve
Steve Gyles

This thread was discussed between 05/12/2010 and 08/12/2010

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