Clutch broken - pedal stays 100% depressed

[m3f_pyite69]

My clutch stopped working today. I think I have a good idea what to check but but I wanted to run it by the forums here to be sure.



There were no warning signs leading up to this -- when I went to drive to work the pedal was incredibly easy to push, but it stayed depressed and the transmission wouldn't go into 1st gear.



I looked at the basics - there is no fluid anywhere (that I can see) and the reservoir is full. I had basically the whole clutch system replaced last year, including the flywheel, master cylinder, slave cylinder, detent pins, etc. and it has run like brand new from then until yesterday.



I was going to check the hydraulic line between the cylinders and re-bleed it. Is there anything else I should check?



Thanks,

Mark

[m3f_greyflyer]

Unless the pedal itself broke (I have had that happen), the fluid had to go somewhere and air went the opposite direction. I doubt bleeding it will fix the problem. Now you get to play leak hunt.

[m3f_pyite69]

The pedal did have a funny side to side motion and would go down an inch or two further if I nudged it to the left a bit, so maybe that is it.



Thanks for the advice, sounds like it will be a fun weekend :P



Mark

[m3f_Jimmy Rustles]

Your clutch slave cylinder is gone. Remove it from the transmission (2 13mm bolts) and take a look.

[m3f_hencini]

When this happened to me, it was the master cylinder, and I knew immediately because there were a couple drops of brake fluid on my shoe.


I would venture to say that at this age MC failures are almost more likely than SC on these cars (as opposed to most other cars where the reverse is true) due to the tendency for the clutch pedal bushings to be totally clapped out, allowing the pedal to put lateral stress on the cylinder pushrod.

[m3f_Jimmy Rustles]

The guy i sold a clutch to had this same thing happen to him and it was the slave. Check both. The slave take 2 minutes to check.

[m3f_hencini]

The guy i sold a clutch to had this same thing happen to him and it was the slave. Check both. The slave take 2 minutes to check.

Slave is certainly the typical culprit in this type of situation, all other things being equal.

[m3f_white-hot]

If it went down and stayed you had a fluid blow and with no fluid pressure to push the pedal up from the floor it just sat there. The return spring on the pedal does not have much effect that far down. I had this happen a couple months ago when the clutch line popped, but it could be either the master or slave. There will be fluid somewhere so get it in the air and have a good look.

[m3f_pyite69]

OK I looked under the car and the fluid appears to be coming out where the oil pan meets the transmission. Clearly not a master cylinder issue, but would a slave cylinder leak come out down there?

[m3f_hencini]

Well, that's *sort of* where the SC is, but it's on the side of the transmission, external to the transmission. Did you inspect the SC itself?

[m3f_pyite69]

Yeah I found the slave cylinder and from the outside it is completely dry; but the fluid is coming from the inside of the bell housing.


It must be leaking through the piston on the inside; I'll replace it and see what happens

[m3f_Jrrrrrrr]

OK I looked under the car and the fluid appears to be coming out where the oil pan meets the transmission. Clearly not a master cylinder issue, but would a slave cylinder leak come out down there?

Yes, once the fluid comes out past the diaphragm of the failed slave cylinder, it pools in the bottom of the bellhousing and drips right where you describe. Most of it probably leaked out and you never noticed at the time, residual dripping of brake fluid could go on for a while.



If you're lucky, the slave pushrod, spring, and rubber diaphragm are still in the bore on the side of the transmission, otherwise you'll need to go fishing for the metal debris in the bellhousing.

[m3f_hencini]

Ah, gotcha. I see what you're saying now. Yes, sounds like you either have a SC leak or a rear main seal leak. Fingers crossed that it's #1.

[m3f_white-hot]

I had a slave do that on a E30, blew all in the bellhousing and the clutch. Talk about a damn mess. Lets hope it didn't get in your clutch. Slave is not too hard to change, just be sure it is lined up on the fork before you use it.

[m3f_tom_m3]

When installing a new slave cylinder don't push the clutch down until the slave cylinder is firmly bolted in. Otherwise you will blow out the cylinder and be ordering a new one. I accidentally did this when trying to bleed one many years ago.