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MG MGA - clutch failure

My MGA failed to restart due to a jammed starter motor last week. The usual tricks didn't help to free it, so we took the ride of shame home.
I found the bendix jammed by a spring from the pressure plate, which means the gearbox is coming out.

Has anyone else experienced this problem or know of a cause? If so, how did you prevent it recurring?
The clutch (standard MGA unit, manufacturer unknown) has done 500 km and was behaving well, without any indication that there was a problem beforehand.

Thanks,
Mark






Mark Wellard

While you have it all apart it might be worth considering changing to the MGB clutch assembly which is better bit of kit. Barney talks about it here: http://mgaguru.com/mgtech/clutch/ct_102.htm

Steve
Steve Gyles

Looks like one of the clutch plate retainer springs Mark, I can't really understand how it broke, but I am pretty sure that you cant buy the individual springs today.
So it looks like you will have to go for a complete replacement clutch. I suppose you may be able to re-use the friction plate but I would probably swap the whole thing.

Here's a pic showing the retainer spring types.(parts 3 and 5)

Cheers
Colyn


Colyn Firth

When my clutch went south some years back. I put an early MGB clutch/flywheel in the car. There are no tricks or complications to doing so and it is well nd is worth the effort. If you are worried about originality, no one will know until the clutch/transmission is removed. Recommend highly.
Bill Haglan

Hi Mark
As Colyn pointed out, it is one of the clutch pressure plate lever retaining springs, They're basically foolproof unless the spring itself breaks, but yours is still in one piece--although it does look as though it's been wearing on something right over on the left of your pic-unusual. They can't be fitted incorrectly, there's only one way to fit them, so something has hit/damaged it.
Normally you'd think that the carbon thrust had failed and the thrust housing had got into it but the spring shows no sign of that, so I'm putting my money on a pressure plate contact pad failure--either one of the three spring seats has broken off or the rubbing pad itself has cracked/broken and come apart releasing the spring----
It'll be interesting to see what happened there-
Is that a TwinCam--they have a different p/plate to the others-?
Cheers
willy
William Revit

Thanks for the replies, everyone.

Converting to a B clutch is an option, Colyn and Bill, but will entail chasing additional parts for the gearbox. I agree that the spring is part #3 in your picture, Colyn. This change would also require flywheel removal for balancing the new clutch.

Willy, I suspect the wear is from its travels around the bell housing before coming to rest against my starter bendix. Unless there's something obviously wrong when I get the pressure plate out, I'm not sure whether to trust it and take the easiest route by just replacing the spring. It is a twin cam but it is a pushrod clutch - a twin cam clutch was not available. the flywheel is the same as a pushrod so there were no fitting problems.

I will be way for about a month, so a chance to open things up and determine the cause will be some time off.

Regards,
Mark
Mark Wellard

Mark you are out of luck, we threw one of those old lever style pressure plates in the bin when clean up at Andrew B’s place. Suggest you go to diaphragm clutch in future or you could go all out with a MX5 gearbox and hydraulic concentric throw out bearing. Gary L. can give you some advice on this upgrade (LOL).
Mike
Mike Ellsmore

The spring may well have got into the ring gear and severely damaged the teeth. It would also account for the jammed starter. I would imagine you are going to be forced to replace the ring gear as a minimum. This makes the MGB option an obvious solution as we've mentioned above. Far better clutch. I went down that route some 20 years ago and never had an attributable issue.

Steve
Steve Gyles

Thanks for the (useful?) suggestions, Mike :-).

A shame the clutch was 'skipped', it might have been useful for parts.

Cheers,
Mark
Mark Wellard

Steve,
At least I can check the ring gear while the g’bo. Is out. I expect it to be ok, given that the bendix was jammed while stopped and there are no scratches on the spring. Time will tell!

Cheers,
Mark
Mark Wellard

Mark
You need to have a look at the other clutch failure thread running------maybe

Thread: Clutch cover assembly height variation
William Revit

Not huge deal to use the MGB clutch - need either a 3 main MGB flywheel or a machine shop that can drill the MGA flywheel peg holes. Much better to get a B flywheel if you can as it is lighter. Also need a non-synchro MGB front trans plate. Barney details it all here http://mgaguru.com/mgtech/clutch/ct_102.htm

I always do this as I've found the diaphragm clutches to be foolproof; the spring type not so much.
Bill Spohn

Thanks Bill, most people seem to be recommending the B clutch.
I will let everyone know how I get on after returning from holidays and getting everything apart.

Mark
Mark Wellard

Mark

If you go for the B unit when you order the driven plate make sure you ask for the correct number of splines to the centre to match the A input shaft.
Also get it bonded as well as revetted.

Derry does all this at BGT
cheers
Ian
Ian Prior

Thanks Ian, good to know.

Cheers,
Mark
Mark Wellard

This thread was discussed between 02/08/2022 and 19/08/2022

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