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MG MGB Technical - Clutch release bearing

I have just bought what was supposed to be an OE carbon clutch release bearing. It has a rolled pin through the carbon ring, and with all the problems that has been reported here with this type I donīt think I will use it.

I also have another carbon release bearing that is part of a Powertune brand clutch kit that I keep as a spare. This bearing has no pin, and looks better finished.

Does anyone have good or bad experience with the Powertune carbon bearings?



I never faced that release bearing problem, but I noticed frequent mentions on BBS.

Often many drivers keeps clutch depress at red traffic light, which ruin a carbon bearing rapidly.
If you want a permanent solution, have a look at:


Jean G.
Jean Guy Catford

Definitely don't use the one with the roll-pin holding the carbon bearing in. They are known to cause problems (see attached, carbon completely broken up after just 8000 miles) and reputable suppliers went back to bonded some time ago. I bought one a couple of years ago and it was bonded.

MGOC sell a roller-bearing release bearing, and I did fit one probably 20 years ago. But it started squeaking and I feared imminent failure, searching online showed things like a pull-off spring so the bearing wasn't continually rotating. My supplier knew nothing about problems with the bearing or the pull-off spring (but maybe they would say that). No change for many years, then a couple of years ago I noticed it had stopped squeaking. Imminent failure? Not yet. Subsequently I realised I had wasted my money, as there was no way I was going to leave that bearing in the next time I replaced the clutch. Even more subsequently I realised the V8 and midget 1500 have them as standard. Would I fit a rolelr bearing to the 4-cylinder again? No. Would I fit one to the V8? Of course.

I changed a pals clutch where the friction plate was completely worn out, but the release bearing had years of life left in it. With the exception of pinned bearings, premature wear is down to the driver.

PaulH Solihull

Release bearing with the friction plate completely worn out, new on left, old on right (obviously). If centered correctly the boss on the clutch can go down inside the release bearing where there is probably more carbon inside than outside.

PaulH Solihull

The attached image shows the release bearing I changed out in January after just 4000 miles of service.

During the last 1000 miles, it always made creeping sound and I knew something wrong. Finally, even the clutch slave cylinder's piston pop out making gear selection impossible.

By the way, does anyone has experience with the following pressure plate with roller release bearing? It looks different from AP heavy duty roller release bearing.

Hong Kong

Ennio Wong

Some serious misalignment of the bearing there, or your carbon disintegrated. Is that a roll-pin near the bottom of the image?

It looks to me like the cover plate and release bearing have to be fitted as a pair, there is no boss on the cover plate as the release bearing is that much thicker, see as opposed to, your link is similar to the V8. The roller release bearing I got from the MGOC many years ago was interchangeable with the standard. Whilst the slave cylinder can cope with a range of thicknesses of friction plate and release bearing - it is designed to compensate for wear in both and the pivots - there is a limit. If it's too thick the piston bottoms in the cylinder bore and doesn't allow the clutch to engage fully. If it's too thin (or the release bearing breaks up) successive prods of the pedal will push the piston out of the end. This may be why some people find the push rod is the 'wrong' length for a replacement clutch.
PaulH Solihull

Yes, it is the roll pin. This is Borg and Beck 3pc clutch kit. Just can't imagine it could wear down to such extend. The carbon did not disintegrate, just worn down due to misalignment as a result of improper mounting of the bearing clips.

I ordered the ebay cover plate and roller release bearing and am waiting for it. I will measure the thickness of the cover and bearing before using. TR7 clutch disc would be used.

Ennio Wong

Thanks for comments, everybody. I have now found locally a bearing where AP and MADE IN ENGLAND is cast in the metal. No pin, and the finish is excellent. Very happy about that.


This thread was discussed between 09/03/2013 and 13/03/2013

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