clutch doesn't declutch

Post by **Pascal** » Mon Jan 14, 2008 3:10 pm

Hi,

Over the last 3-4 months my clutch has started playing up. I first noticed an excessive free play in the pedal, making it difficult to declutch and change gear. I tightened the nut on the adjusting rod and everything went back to normal for a few weeks. Then same thing happened again, so I tightened the rod more. I had to do that a third time a few weeks later but then the pedal action became rough. Now the travel feels normal but the clutch hardly declutches.

Is that a symptom of worn clutch or something else? Any idea? From my experience of other cars I thought that a worn clutch was a slipping clutch.

Regards

Post by **crossword** » Mon Jan 14, 2008 3:24 pm

A good test for a slipping clutch is , whilst travelling up hill at say 35 mph in 4th gear , to press hard on the accelerator. If the engine speed increases but the car does not accelerate, your clutch is probably slipping . If not it may be that your adjustment of the clutch travel is compensating for a worn clutch release bearing , which on the minor is a carbon ring . The roughness you describe may be the carbon breaking up . It may be possible to see the release bearing through te holes in the gearbox bellhousing whilst underneath . Pull of the grommet on the left side as the release lever on the other side will limit your access . Good luck

Post by **badfelafel** » Mon Jan 14, 2008 3:46 pm

Before doing anything expensive, check the position of the adjustment nut when you tighten it - is there a check nut? Its possible that the vibration of the car is playing with your nut and loosening off every so often - mine does that:)

Also make sure you havent over tightened it.

Post by **Pascal** » Mon Jan 14, 2008 3:55 pm

There is a check nut and the second time I adjusted it I put some lock'n seal, so that should have kept it in place. I suspect something must have gone wrong because in April I drove 1200 miles around Ireland without any problem, and now I would have to re-adjust it every 100 miles or so.

Post by **Axolotl** » Mon Jan 14, 2008 4:52 pm

If you've checked that it isn't the linkage giving way somewhere along it's travel, I'd agree with Crossword, that it is probably the release bearing giving up the ghost. A worn clutch would de-clutch very quickly, because it would basically be slipping before you even pressed the pedal.

The worn release bearing would also explain the vibration you're getting because as the carbon ring gets thin, it starts to break up, so you have a bumpy surface meeting the clutch release arms, instead of a nice smooth one. Eventually, the carbon ring will go completely, leaving you with metal to metal contact, and probably a nice squeal to go with it.

Unfortunately, to replace it is a gearbox off / engine out job, whether it is the release bearing or the clutch itself. Once you've gone to those lengths, it would make sense to replace both.

Post by **RogerRust** » Mon Jan 14, 2008 5:02 pm

sounds like the clutch relay shaft to me.

this thing

or more likely the brass bush and rubber mount at tone end or the tufnell bush at the other.

On my traveller it had the same prob and the brass bush was worn through.

Post by **Pascal** » Mon Jan 14, 2008 5:13 pm

Well that would be handy as I've just ordered all these bushes. How easy is it to take out the clutch relay shaft? I could try to replace the bushes myself before taking the car to the garage for a complete clutch replacement.

Post by **RogerRust** » Mon Jan 14, 2008 5:22 pm

Here is the old brass and rubber bush.

Shouldn't take long to do there are only a couple of bolts at each end of the shaft. I also replaced the two metal strips that connect it to the clutch actuator shaft.

The whole thing only took about an hour.

Good luck.

Post by **crossword** » Mon Jan 14, 2008 5:30 pm

Not too difficult but slightly fiddly . Two bolts attach one bearing housing to the side of the gearbox . At the other end of the shaft is another bearing housing this time fastened by two bolts onto the chassis . The bearings are spheres of tufnol or bronze drilled in the centre to take the shaft . The slight fiddliness is because one end of the shaft also has a spring on it so the assembly has to be squeezed between the chassis and gearbox .
Whilst you are in that area I suggest you check that the gearbox steady cable is intact . This is fastened between the rear of the box underneath & to the gearbox crossmember . If broken this could allow the box to move forward as the clutch is pressed & reduce the travel of the clutch rod .

Post by **bmcecosse** » Mon Jan 14, 2008 8:15 pm

But do take the advice above - and have a look inside at the release bearing carbon ring. If it's gone - then you will need to get at the clutch to fit a new one - and if you are taking the gearbox out anyway - that's the time to sort out the bushes.

Post by **dunketh** » Tue Jan 15, 2008 9:27 am

My moneys on the CRB. My car suffered exactly the same symptoms when my bearing disintegrated.

Post by **Pascal** » Thu Feb 07, 2008 1:45 pm

Spot on... The clutch was ok (but replaced it anyway) but the carbon bearing was crushed.

The source of the problem was worn bushes on the clutch relay shaft. My corrective action of tightening the adjusting nut just resulted in a destroyed bearing... I'll know better next time!

Regards

Post by **bigginger** » Thu Feb 07, 2008 1:52 pm

"tufnell bush" - not seen this before, so I Googled it. It's pretty rare to get no relevant hits at all

a

Post by **Axolotl** » Thu Feb 07, 2008 3:47 pm

tufnell bush" - not seen this before

Me neither. Then I worked out it's "tufnol" (as per Crossword's post above). Google that and you get the idea.

Post by **bigginger** » Thu Feb 07, 2008 5:00 pm

Aha!
a

Post by **RogerRust** » Thu Feb 07, 2008 7:01 pm

bigginger wrote:"tufnell bush" - not seen this before, so I Googled it. It's pretty rare to get no relevant hits at all
a

With my south london accent tufnell and tuffnol sound the same as do ball and bull.

Post by **bigginger** » Thu Feb 07, 2008 7:21 pm

I wasn't taking the *^%& - I just have a rule about looking up any words I haven't heard or don't understand

a

Post by **RogerRust** » Thu Feb 07, 2008 7:36 pm

I think i heard the word from my father who almost certainly said tufnell! I remember him telling me it was like bakelite made by soaking cloth in phenol and formaldehyde and heating it under pressure. I guess that in polymerises.

I'd like to try and make my own rogelite fittings but would probably get a call from the anti terrorist branch for buying the chemicals.

I'm not sure but I think Linoleum is made in a similar process using linseed oil and formaldehyde.