8 replies to this topic

[robin356a]

Rover Cooper (Carb model)
1990

Just coming to the end of some seasonal maintenance and the clutch (which I did not touch and was working perfectly before) is now refusing to disengage.

I did replace the gear selector shaft o-ring and after reinstalling the rod change I checked gear selection. All gears selected as they should and while the car is off its wheels the clutch seemed okay and the front wheels turn as they should.

But once the car is back on the ground there are no signs of forward motion and no indication of the clutch biting as the pedal is released, I then jacked the front up again and the wheels spun as before.

I've bled the clutch and checked the slave cylinder piston is moving as it should, all seem fine.

Am I missing something or do I need to start dismantling the clutch and accept that the joys of mini motoring will not be happening today.


Any ideas?


Robin

[Cooperman]

Are you saying that the clutch is permanently dis-engaged with no drive from engine to gearbox (or, perhaps, from gearbox to wheels), or will the clutch not dis-engage the drive leaving the drive permanently to the wheels?
The former would be very unusual and would have to be either a mechanical linkage issue of some sort with something jamming the linkage and preventing the arm from disengaging the release bearing from its contact with the clutch diaphragm via the 'top-hat' fitting (never seen this) or where a car has been standing for a very long time and the clutch centre-plate has become corroded onto the pressure or driven plate and will not disengage.
If it's the latter, then it is either hydraulic or a linkage problem and you need to ensure that the top of the hydraulic arm moves not less than 0.5" full travel when the pedal is pushed right down. If less than 0.5" it's a hydraulic problem, if 0.5" or more, then it's a mechanical problem.
I hope this helps.

[robin356a]

Are you saying that the clutch is permanently dis-engaged with no drive from engine to gearbox (or, perhaps, from gearbox to wheels), or will the clutch not dis-engage the drive leaving the drive permanently to the wheels?
The former would be very unusual and would have to be either a mechanical linkage issue of some sort with something jamming the linkage and preventing the arm from disengaging the release bearing from its contact with the clutch diaphragm via the 'top-hat' fitting (never seen this) or where a car has been standing for a very long time and the clutch centre-plate has become corroded onto the pressure or driven plate and will not disengage.
If it's the latter, then it is either hydraulic or a linkage problem and you need to ensure that the top of the hydraulic arm moves not less than 0.5" full travel when the pedal is pushed right down. If less than 0.5" it's a hydraulic problem, if 0.5" or more, then it's a mechanical problem.
I hope this helps.

Thanks for the quick response

Unfortunately it's the former, the car shows no sign of any forward motion when in gear with my foot off the clutch pedal entirely. The car has only been off the road for 5 months inside my garage, would that make corrosion unlikely?

Robin

[Guess-Works.com]

Most likely that the plunger has stuck in...

does the pedal feel really light or has it gone solid as a rock ?

[robin356a]

Most likely that the plunger has stuck in...

does the pedal feel really light or has it gone solid as a rock ?

The clutch pedal feels normal, I can push it to the floor without it binding or jamming at all. Don't know if photos will help (although there's not much to take pictures of with this fault).

This is without my foot on the clutch pedal.



This is with the clutch pedal pressed to the floor.



Is there any more information I can give you that may help with the diagnosis?


Robin

[Cooperman]

Look at the big nuts in the centre of the clutch cover. They are the overthrow stops and when you have the pedal pushed right down they should be touching the casing with no gap. When you take your foot off the clutch they should move away from the casing as the release bearing plunger pulls away from the clutch diaphragm. if these nuts don't slide back when the clutch pedal is lifted, then there is a mechanical jam, probably the plunger itself seized in the housing which is holding the release bearing against the clutch diaphragm and holding the clutch disengaged.
You will need to buy some penetrating fluid (no, not WD40, that's not a pen. fluid) and with your foot off the clutch, get some fluid into the plunger bore. I would remove the clutch arm and pour the fluid in where the small ball-end on the arm goes into the plunger. try to prise the plunger out a little with a screwdriver against those locknuts/overthrow stops, but don't try to turn them with a spanner without first removing the clutch operating arm or you risk snapping the ball end off (been there, done that!). Then get the pen, fluid all around the area of the plunger until it moves freely in and out about 0.15". When it moves freely, lubricate it with thin oil (like 3-in-1), reconnect the operating arm and it should work OK. It may be necesary to re-set the overthrow nuts.
The reason the plunger seizes is because it's a steel plunger in an aluminium bore.

[Guess-Works.com]

From the pictures, the clutch hydraulics are functioning normally, which means the fault lies deeper...

I'm afraid you will need to remove the clutch/flywheel assembly for further investigation.... also check the primary gear is driving the gearbox

[robin356a]

I finally have the clutch out and this is what the clutch plate looks like, doesn't seem to be much left, some of the rivet heads are starting to be worn away.

[robin356a]

I'm not sure if it's possible to change the title of a thread but if I could it would now be;

'I Did Something Stupid So In The Future You Won't Have To.'

Before I go into details let's look at the positive results;

1. I have replaced my clutch.

2. I now know that if I did need to remove my engine, strip it down, rebuild it and reinstall it into the car, it would not be a problem for me.

3. The engine bay is much tidier and rust free.



But the stupid thing I did was to Install My Driveshafts The Wrong Way Round, this means the driveshafts are inserted further into the outer CV joints and only just locate on the splines of the inner joints. This gives enough drive for the wheels to turn when the car is in gear and on axle stands as there is no force acting against the turning wheels. But as soon as I put the wheels on the ground the driveshafts would instantly jump off the splines when I tried to drive the car in any gear meaning no forward motion and my first thought that the clutch was not disengaging.

Luckily there was no damage to the splines and I have a month now of driving with no issues from the engine.

Thanks again to everyone who gave advice on this thread.

And finally a picture of Isabella who is back on the road where she belongs.