Clutch Trouble

[Faheem]

So the project car is almost done.

When I bought the car it had a clutch problem, the disc was completely worn so that the car wouldn't move at all.

I've replaced the clutch, flywheel and pressure plate and that was done just over a year ago.

Today I started the car and reversed it out of the drive. I left the car in reverse, turned the engine off and went about my way. Half an hour later I tried to start the car but the car would not go into any gear at all whilst the engine is running.

There were no other symptoms prior to this and after having the clutch fitted I've done about 300 miles.

Now the pedal feels incredibly light and unless the car is turned off I cannot get it into gear.

Even if I put it in gear and try and start the car with the pedal flat to the floor the car jerks and stalls.

There is very little resistance at the clutch pedal....

Any ideas please?

Incredibly annoying as everything was done and I'd booked for an mot today and now this has happened.

Thanks for reading.

 

[Antm72]

Sounds like a fluid/ slave cylinder issue to me the clutch is obviously not disengaging hense you can not select a gear .
I take it if you try starting in a gear the car lurches ?

 

[Faheem]

Yes @Antm72 car lurches forward and stalls.

Fluid wasn't changed after clutch replacement. Could that be it?

 

[Antm72]

It sounds like the pedal is doing nothing the clutch is hydraulic so it may be worth checking no pressure is being applied to the clutch release plate so you can not engage / disengage the gearbox.
Can not see it being much else unless you hsve had a big failure.
Any fluid leak seen ? Levels good ?

 

[Faheem]

No fluid leak, transmission is wet but not dripping. Topped up with atf fluid and it only took 300ml. Which is a fair amount but made no difference to the pedal after.

 

[t-tony]

You will need to bleed air out if the system now Faheem. My guess is the new clutch has required the slave cylinder to "travel" further and has finished off the seals in the cylinder. Aren't cars fun ?? A big learning curve mate.

Tony.

 

[Faheem]

How would you Bleed the air out of the system? Is that the slave cylinder I should be bleeding?

Cars are fun but not so much when you get everything done and then a major issue like this pops up unexpectedly.

 

[Faheem]

So the cylinder is out. Not sure what to do now. Bleed existing cylinder or buy a new one?

 

[colb]

I would replace it with a new one, you could strip the old one down and put new seals in it using a seal kit but the bore might be pitted which would wreck any new seals installed. Easier to replace it then bleed it as you would doing brakes.

 

[raymond]

Master cylinder could be at fault.

 

[Faheem]

I attached the slave cylinder back onto the clutch hose, after which I opened the bleeding screw and tried to push the piston in by hand hopefully removing any excess air or fluid, however it seems that no fluid comes out of the Bleed nipple despite the cylinder being connected to the clutch hose and the piston pressed in repeatedly. Is this normal or does it indicate that the seals have failed.

 

[colb]

If no fluid is getting to the slave then sounds like the master cylinder is at fault, instead of pressing the slave rod in and out you need to use the clutch pedal to force the fluid down to the slave cylinder and bleed it at the slave. If you don't get fluid out of the slave it could be the seals in the master have given up and need replacing or fit a new master.
http://www.realoem.com/bmw/enUS/showparts?id=CM12-EUR-12-1999-Z3-BMW-Z3_19&diagId=21_0059

 

[lightning]

Pumping the slave cylinder piston in and out will not result in fluid coming out.
You need to close the bleed nipple and do it from the master cylinder end.
But it sounds like either your master or slave cylinder is faulty.

 

[Faheem]

@colb I've removed the clutch hose from the slave cylinder and am pushing down the clutch repeatedly. I hear air being pushed through the hose but not the tiniest bit of fluid.

Does this then indicate that the master cylinder has failed? Wouldn't that stop the brakes from working too as they use the same master? The brakes are working fine.

 

[hard top]

The brakes are working fine.

You hope......

 

[colb]

If there is fluid in the shared reservoir then it would indicate a fault within the clutch master cylinder, sounds like seals have gone and fluid is just passing by them instead of being pushed down the line to the slave. Any signs of leakage at the clutch master cylinder?

 

[Faheem]

This here is dry as a bone.

Here's a video of what the clutch hose looks/sounds like when the clutch is pressed.

View: https://youtu.be/L_zE33PyTGQ

 

[colb]

OK that sounds like only air being pushed down the feed pipe, odds on its the seals in the clutch master cylinder gone bad.
The Clutch master is a single unit operated by the clutch pedal, it only gets its fluid from the shared brake reservoir, if that's got plenty of fluid in it the fault must be in the clutch master cylinder. I would replace the unit, don't mess about with a seal kit.

 

[Faheem]

Okay thank you @colb I'll replace the master cylinder. @Synclare could you possible help me out with a master cylinder? (as you're closest to me) more than happy to pick up

 

[Faheem]

@colb I've had a look at the master cylinder and there are no signs of leakage around the cylinder.

I was under the impression that if it fails the cylinder would leak fluid?

It is the only logical explanation however, as the brakes do work, I'm just a little confused as this happened without any warning at all. It wasn't difficult to put into gear this morning and the clutch assembly seemed to work correctly, how would it fail altogether at once?