Intermittent Clutch Slip

[db7gtgrigio]

A friend has just acquired a very nice S1 2+2 and he says that "sometimes" when giving it a bootfull at low revs the clutch slips although it is not all the time. I have not driven the car however the clutch pedal movement feels very strange, not a smooth consistent pressure going to the floor but more a couple of incremental positions in travel as you push the clutch pedal down. It is firm, then mushy, then firm. weird.

I crawled underneath as far as I could and could see that there is a spring on the clutch slave. However, the car is in the number range for the hydrostatic slave.

I would have thought that a malfunctioning slave would have made gear engagement difficult, not clutch slip.

Any thoughts??????

[abowie]

In my limited experience if it slips it's either oil on the driven plate or it's worn out.
I'd ensure that the hydraulics are ok first (flush, replace both cylinders etc). You might get lucky. As you say, if the thrust bearing is worn and the slave doesn't compensate you'd expect it to incompletely disengage.
If and when this doesn't solve the problem; I'd replace the clutch.

[mgcjag]

Hi Chris......if the pedel feels strange then as Andrew says above bleed it, this causes poor engagement....... if you want to check for a slipping clutch stop the car engage a high gear and try to pull away, it will either slip or try to pull away and stall

[Hugo]

You say it should have a hydrostatic clutch cyl., i.e. self-adjusting, with no spring? But it has a spring? I wonder if the precious owner might have fitted the spring in an attempt to stop it slipping?
To find out where the fault lies, all you need to do is check whether there is any slack at the end of the clutch fork, or whether it is under pressure. Normally, with a self-adjusting cylinder, you should be able to push the piston further back into the cylinder, but as this one has a spring who knows what is going on. If the piston is already fully retracted and the linkage is still under pressure then it's bound to slip. If there is free play at the end of the clutch fork, then it needs a new clutch.
Your description of the feel of the pedal sounds like a diaphragm clutch (heavy at first, then lighter as it goes down) that is getting too much travel and getting stiffer as it reaches the end of its travel. But that's just a guess of course.

[db7gtgrigio]

In my limited experience if it slips it's either oil on the driven plate or it's worn out.
I'd ensure that the hydraulics are ok first (flush, replace both cylinders etc). You might get lucky. As you say, if the thrust bearing is worn and the slave doesn't compensate you'd expect it to incompletely disengage.
If and when this doesn't solve the problem; I'd replace the clutch.

If replacing the clutch hydraulic slave cylinder would it be preferably to go with

a) the original early adjustable s1 slave (short)
b) the hydrostatic one that was originally specified for this specific car (not even sure if these are available); or
c) the later S1/S2 adjustable slave (long)

or is it all academic??????.

[abowie]

I honestly have no idea. I don't really understand how they work differently or why Jaguar changed them. I personally fit short slave cylinders with adjustable rods and springs to my cars as this seems the most sensible arrangement to my mind. I may be completely wrong.