Clutch Release Bearing Life Expectancy?

Post by **dunketh** » Wed Nov 07, 2007 5:01 pm

Does anyone have any idea as to how long one should last?
I fitted a brand new one in May and have already noticed my pedal 'free play' has extended quite a bit.

I've not actually had a look inside yet so it may be fine.

I just don't fancy having to replace it again so soon.
I do try to knock it out of gear and not 'ride' the clutch but often I have no choice. There are lots of hills locally where traffic frequently stop-starts and riding the clutch is the only way to keep moving.

What would be considered excessive abuse of the clutch?

I do a lot of miles in a year but surely these bearings should last a fair old time?

thanks
jon

Post by **simmitc** » Wed Nov 07, 2007 6:10 pm

I'd expect at least 80,000 miles, and have had cars with 120,000 plus on the original bearing. Regular adjustment is essential; but I too have noticed that newer bearings don't seem to last as well as the originals. Now that reminds me of discussions on the quality of parts ......

Post by **bmcecosse** » Wed Nov 07, 2007 8:35 pm

Riding the clutch will kill it in no time. On these cars it's a lump of graphite - every time your foot is on the pedal - it's wearing away. Can only suggest you hang back slightly on the hills - then crawl forward in 1st gear - with foot NOT on clutch pedal.

Post by **dunketh** » Fri Nov 09, 2007 10:54 am

On these cars it's a lump of graphite

You say that as if its 'uncommon' in the wider gearbox world.
Based entirely on my interpretation of your comments does this mean there could be an alternative available?

Surely as long as a bearing fits over the shaft it could be made to fit with some fork fiddling.

Are there any other cars out there with a similar setup that employ a harder wearing material?

Post by **Kevin** » Fri Nov 09, 2007 11:16 am

Is there not a ball bearing kit thats available to convert to a hydraulic clutch from some of the specialists.

Post by **bmcecosse** » Fri Nov 09, 2007 11:35 am

Graphite wasn't uncommon in the 'old days' - the problem is that the release fork travels in an arc - and so any fixed bearing will not always be concentric with the clutch. Modern cars have a linear movement for the release bearing - don't suppose it's beyond the wit of man to adapt one to an A series box - maybe it's been done already?

Post by **MoggyTech** » Fri Nov 09, 2007 1:39 pm

You can extend the carbon thrust bearing life by applying just a smear of copperslip to its face. You can do this with everything in situ, by removing the rubber bung on the lower LH side of the bellhousing, and use a small paintbrush to apply the copperslip, but just a smear no more. It will eventually burn off, but can be re-applied every 1000 miles or so. Plus of course do not ride the clutch unless absolutely neccessary.

Although the clutch lever does indeed travel in an arc, the bearing is free to swivel about the mounting point, so if you could find a race bearing type that would fit, and have the required clearance it would work fine. As soon as the outer edge of the bearing contacts the pressure plate, the bearing swivels flush to the plate. There might be a slight side load on the bearing compaired to a linear actuated bearing, but it would be minimal.

Bearing life depends on driving habits and type of journey. Long motorway trips, the bearing will last for ever. Lots of town driving in heavy traffic, perhaps 30,000 miles give or take. At least you know when it's shot, there is a loud screech when the carbon retainer contacts the pressure plate

Post by **dunketh** » Fri Nov 09, 2007 2:30 pm

Lots of town driving in heavy traffic, perhaps 30,000 miles give or take.

So thats a little over two years of real use then?

I can live with that. Pulling the lump out is all good fun really anyway.

Post by **MoggyTech** » Fri Nov 09, 2007 3:40 pm

dunketh wrote:
Lots of town driving in heavy traffic, perhaps 30,000 miles give or take.
So thats a little over two years of real use then?

I can live with that. Pulling the lump out is all good fun really anyway.

Maybe even more if you really look after the Moggy clutch. It is not unknown for Moggy and MG clutches to die after as little as 10K if used harshly.

Given that few Moggy owners will cover 15,000 miles per annum! the 'average' use of 2,000 to 5,000 miles per annum, will see the release bearing last a long time, but worth fitting a new bearing anytime the engine or gearbox come out for other work.

Post by **M25VAN** » Sat Nov 10, 2007 8:35 am

http://morrisminorspares.co.uk/shop/pop ... p?pID=1180

This is similar to what I fitted as part of a hydraulic clutch kit many moons ago. The hydraulic bits got removed a while back but I left the release bearing in place. Has done well in excess of 100,000 miles and is still working ok if a bit noisy but then I have no carpets !

Post by **dunketh** » Sat Nov 10, 2007 8:45 am

Wow!

Thanks for that.

I'm going to by one of them. I didn't know they were this easily available.

the 'average' use of 2,000 to 5,000 miles per annum

lol.. If only I could say the same! Its no wonder most minors I see are so pretty and well kept.

Post by **alex_holden** » Sat Nov 10, 2007 9:10 am

M25VAN wrote:http://morrisminorspares.co.uk/shop/pop ... p?pID=1180

This is similar to what I fitted as part of a hydraulic clutch kit many moons ago. The hydraulic bits got removed a while back but I left the release bearing in place. Has done well in excess of 100,000 miles and is still working ok if a bit noisy but then I have no carpets !

Is the curved section that touches the pressure plate made of graphite? Because the angle the arm moves through means the release bearing is never going to run quite concentric with the flywheel.

Post by **M25VAN** » Sat Nov 10, 2007 4:30 pm

From memory the curved section is metal, it's definitely not graphite. When I bought the hydraulic kit this was sold as an extra to give a fully self adjusting clutch as it doesn't wear down like a graphite bearing does. Not sure if it is really worth it to fit by itself although I guess it makes for less frequent clutch adjustments. I just left it fitted to the release fork when I went back to a mechanical linkage.
Out of interest has anyone had a clutch wear out? I've always put in a new clutch whenever I've replaced an engine and have never had one wear out. I notice however that they have become a bit expensive so will be made to last it bit longer in future !

Post by **bmcecosse** » Sat Nov 10, 2007 6:31 pm

This looks good - and if your's has lasted 100k miles - well - sounds unbeatable. I'm guessing the 'curved' face is to minimise the effect of running off centre on the clutch pad.

Post by **NZJLY** » Mon Nov 12, 2007 8:45 am

Just as an odd suggestion, what about a plastic bearing? eg http://www.bostongear.com/products/bearings/molded.html

We could purchase via the MMOC to get enough units made. I would be happy to trial one, but postage would not be pretty

Anyone with experience with plastic bearings?

John

Post by **dunketh** » Mon Nov 12, 2007 10:00 am

Plastic Bearings?

I remember my old Fiesta used to have 'phenylawotsit' (that stuff they make carb spacers out of) bearings on its suspension strut tops.

They were designed to last the life of the car and then some!

Out of interest has anyone had a clutch wear out? I've always put in a new clutch whenever I've replaced an engine and have never had one wear out.

Funnily enough - No.

I've replaced my bearing once, and replaced the clutch as a matter of course. The old one was perfect aside from some slight glazing.
I cant say I've ever seen a properly worn out friction plate.