Clutch Problems

[Chris Edgar]

http://www.mmoc.org.uk/viewtopic.php?f=4&t=49267

In my previous post, above, I mentioned a very heavy clutch pedal. I had a 2nd hand gearbox ready so I decided to change the gearbox & at the same time, renew the thrust bearing.
My present gearbox was leaking oil a lot & becoming very noisy in first gear.
I took the box off under the car & was astonished at the state of the brearing, a large piece having broken off at some time. This bearing was fitted a little over a year & 5000 miles ago.
See photos....


Put the new bearing onto the "new" gearbox & attempted to fit this while lying on my back, on the garage floor, under the propped up car....NO CHANCE. I had feared this may well be the case in the planning of the job & so it was..
Several attempts to line up, swivel the box & push together failed & I was concerned that damage may eventually be caused so I gave up & proceeded to remove the engine, then fit the box & then replace the engine.
So the job took ages longer than expected.

All was now fine & dandy...but today ( about 50 miles after the job finished), suddenly, the gears will not engage without crunching big style.
The pedal is correctly adjusted, it "feels right" when depressed & the engine perceptably slows as if all is working well so I am at a loss as to what is wrong.
Dreading the thought of having to do it all again!!!

Anyone... any ideas pleeeease!

[Chris Edgar]

trying to attach photo, but if not, almost half of the graphite had broken off

[mike.perry]

If it is a 1098 clutch try a roller bearing thrust bearing. More expensive but better wear

[Chris Edgar]

No it is 948, Mike.

I had fitted a new clutch & thrust bearing abot 5000 miles gao, a year gone December.

Bearing ( & gearbox) replaced over this weekend.
It is as if the driven plate has suddenly started dragging after 50 miles of perfect operation today...but why?
Is there something wrong with the clutch as opposed to the new bearing, or the linkage. I did not replace any parts of the relay shaft although I planned to order new bits & pieces for it tomorrow.
There is no-one here at the moment who can depress the clutch while I lie underneath & watch what is happening..will be tomorrow though.

Presuming the linkage is all working OK...
Came across this diagnostic aid on a Mini forum:

C. THE CLUTCH ASSEMBLY
1. Failure of clutch diaphragm spring due to fatigue or distortion
2. Centre plate hub not sliding on primary gear splines.
3. Clutch plate surface de-laminating or breaking up
4. Distorted clutch plate.
5. I fitted, clutch plate shock springs broken and causing a ‘jam’.
6. Primary gear not rotating freely on crankshaft due to either i) Insufficient primary gear end float, ii) Primary gear bushes seizing on crankshaft, or iii) Primary gear bushes breaking up

I will be very angry if it is a problem withi the clutch, they should last years!

[Chris Edgar]

Well...hopefully may be fixed now.

With a glamorous assistant working the clutch pedal, I was able to watch the linkage from underneath & see that there was a bit of movement in the plate which contains the rubber & bronze bushes.
That is, one of the bolts was not tight enough...! Sloppy workmanship/
Now both bolts are very tight & all is OK, no crunching at all.

I hope that is the end of the matter!

Thanks.

Chris

[bmcecosse]

As you found to your cost - it is MUCH easier to just move the engine to get access to the clutch. Doesn't need to come out - just slide/twist it forwrad in the engine bay - rad + towers removed. Make sure you have a good 1" of free play at the pedal - and NEVER sit with foot on the clutch.

[Chris Edgar]

This problem just won't go away... the majority of the time all is well....smooth operation, no trouble at all.

BUT, every so often, after starting the car, none of the gears will engage without big crunching. This will persist throughout the drive, and, after stopping next time you start up & drive ...amazing...all is well ?????

I got it in my mind that one of the thrust bearing clips may have come off & whipped the engine out late last night, but no, all well there.
This morning I will dismantle the clutch to have a look at the driven plate etc.

Bearing (no pun intended) in mind that all this has come about after fitting a different 2nd hand gear box, could this intermittent problem be in the gearbox & if so, why does it work perfectly most of the time?

Any suggestions please before I end up buying a re-con box for hundreds of pounds only to find that the problem is not fixed.

thanks

Chris

[bmcecosse]

Correct (engine) oil in the gearbox? First motion shaft binding up in the bush in the end of the crankshaft?

[Chris Edgar]

Yes I put the correct oil in, Roy.
Why might the first motion shaft bind...bent?
How would I know that the 1st motion shaft was binding? & could that happen intermittently?

Since my post this morning I have dismantled & had a good look at all the clutch components, cleaned them, checked that the driven plate slides easily on the splines & put all back together & engine back in.
All runs perfectly, but then it did before. Except for the odd occassion when it crunched into all gears as described previously....time will tell.

[kennatt]

it's possible that when you were having trouble mating the engine and box(Laying on your back etc) that the end of the first motion shaft just turned the edge of the spigot bush in the engine,taking it apart and putting back together may well have removed this edge and hopefully all will now be ok.
anyway you are now realy good at fitting clutches

[lambrettalad]

I had a very similar problem with a triumph 2.5 PI turned out to be the drive plate sticking on the shaft,cured by a very tiny smidgin of gold copperslip

[Chris Edgar]

Many thanks for all the comments & advice . Greatly appreciated.
Off out this evening, so we' ll hope for the best.

Yes, practice makes perfect or, at least, improves...
Time to take engine out ....now only just over 1 hou.

Chris

[1mustard]

mate i am having similar problems with my convertible, i have restored the car, been in bits for about a year, the clutch was a recon type which worked perfectly and is in good condition, same thing it wont clear and just crunches evrytime, incredible!! i am at a loss to explain it, luckily i have a ramp and i make short work of getting the box out, i dont take the engine out, i spin it and am a bit brutal with getting it in and out!, but its not easy, and i appreciate doing it on your back would be hard work.
I would say i dont put every component back, before checking, a few bolts and the linkage, support the box and check it before i put it all back together, if its right i will work.
It is worth checking the pilot bearing in the flywheel as suggested by the other lads, to be honest you would have clear marks on your gearbox first motion shaft if you had a problem there, also i am going to check my bearing/arm arrangement as i too fitted a different gearbox, and i didnt realise there is different bearing arms and also different bearings for different ccs, failing that i will have to cough up for a new clutch, which pains me as it looks perfect, i have put the original box back in with the original clutch and it still drags!, i am going to give it another go tomorrow.
As your one is an interrmitant problem i appreciate it must be really annoying and even trickier to get to the bottom of, perhaps your pressure plate is a bit ''iffy'', i fitted a brand new borg beck kit in my traveller last year and although it works perfectly, from day one it occassionally makes a funny noise and i don't think its the best quality.

Good luck hope you suss it out.

[Chris Edgar]

Thanks..have a look at this thread:

http://www.mmoc.org.uk/viewtopic.php?f= ... 5&start=15

very interesting!

Mine is working fine now & has been since I put it all back together after my last post.
I did not notice if any of these nuts on the pressure plate was working loose but did not specifically look at them.
Several people suggest that pressure plates should not be replaced as a matter of course when the driven plate is renewed...there being concern that some of the new stock is poor quality, which certainly seems to be the case when you look at the above thread.