Grant27

So I just got done doing my last run at autoX today and the clutch in my 86 951 completely gave out.

It was dropped completely to the floor like as if a spring was holding it there.

I shut the car off and reached down and was able to pull the clutch up by hand to where it would come back to the correct position and stay there

But then when I would push the clutch down a little it would pop down to the floor like it was being pulled by a spring again,

Any help would be greatly appreciated!!!!



The above text was my original post, I have since revised it to help serve as a thread for helping anyone fix their clutch issues. Feel free to PM me, but don't mistake me for an expert. On one of the further pages there is a very helpful video showing basic clutch operation, detecting leaks, and a great way to bleed the system (toughest part of changing out the slave and/or master cylinder). Cheers!

Brantley

Check the clutch / brake fluid reservoir. It full? If proper fluids, sounds like the clutch master and/or slave cylinders has failed. Usually, when the master cylinder fails, the seals fail and release the brake fluid in to the drivers foot well behind the clutch pedal. Any fluid behind the clutch pedal soaking into the carpet?

Tom M'Guinn

+1

Would suggest you save the extra effort and replace the master, slave, and hose between them all at the same time. Shortly after getting my car, I had to change the slave. Then a month later I had to change the master. Then a month after than I had to change the hose/pipe between them. Also, get a Motive power bleeder -- it's a huge pain to bleed the clutch the old fashion way.

Grant27

Thanks for the info!

There is not any leaks under the car or in driver foot well, the fluid is right to the max fill line like it was a couple days ago when I checked it.

I am wondering if something like a linkage could have gone wrong.

Does anyone know of any connections between the pedal itself and the clutch cylinders?

Brantley

The brake fluid is shared by both the brakes and the clutch. So, the system was designed such that should the clutch master / slave cylinder fail, the brakes wouldn't fail - and, the fluid reservoir will remain full. So, the fact the reservoir is full doesn't indicate there isn't a problem with the master / slave / line between the two.

There is a diagram on Clarks here -

http://www.clarks-garage.com/shop-manual/clutch-04.htm

There is a spring, part 16 that you could check. But, the fact is if the pedal goes to the floor, there isn't anything wrong with this spring. The clutch master / slave cylinders are the problem and when bled properly should force the clutch pedal back up as pressure back from the clutch fork. Did any air get in the system? Perhaps you just need a good bleeding?

951Saga

Check the clutch fork condition. Look throught the inspection hole on the bell housing near the clutch slave cylinder and starter. If it moves freely it is broken.

Brantley

ahh, yes, good call. If it isn't either of the cylinders and the fluid is bled properly, it is probably the clutch fork (broken, etc).

Grant27

How bad of a process is replacing the clutch fork? I didn't see that on clarks.

I will check the springs and other linkages under the dash as well as the clutch fork ASAP.

Thanks for the great info! I am hoping it is a linkage...

Red1

This is most likely the necessary fix. A broken clutch fork is not impossible but not near as common.

And can't stress enough the usefulness of the Motive bleeder. Really takes the work out of a m/c swap.

Grant27

I am just surprised that something with the hydraulic system would fail in such a quick way, from full operation to complete loss of pedal action.

I will still inspect the things I mentioned in the last reply.

If nothing is seen there I will launch into the master/slave replacement process...

Red1

That's how it goes.

If it is the clutch fork, you may consider full clutch replacement, because you'll have the pressure plate exposed when you get the fork out.

But if you were running a stock clutch it's probably not the fork. That's more commonly an issue for guys running heavy aftermarket pressure plates. I am one of those guys and I have yet to break a fork.

The m/c and slave aren't hard jobs, but the bleeding can be a bitch. Get the Motive.

Grant27

I actually have got a pump that had a brake bleeding tool that I have used with good results, does it need to work the same way? It is the mityvac brand.

Clarks said a new master cyl is around 60, how much for a slave cyl do you guys estimate?

Tom M'Guinn

www.pelicanparts.com (west coast)
www.944online.com (east coast)
www.paragon-products.com (middle)

Any of these guys will be able to fix you up with parts. I think they all sell the Motive Power Bleeder too. The Motive is like a bug sprayer you pump up to put pressure on the fluid from the reservoir end, rather than a vacuum pump that tries to suck it out via the slave cylinder. I've used both together at times, but the Motive is the key...

Grant27

Well pelican has the best prices so I will inspect the car and order some parts.

Thank you to everyone helping me out so quickly, this site really is a blessing for guys like us!

400hp944

Check the clutch fork pivot shaft. It has a small set screw that holds it in place. If this screw backs out, the shaft can come out. I had this exact thing happen to me - just as you described... I doubt it is a hydraulic failure.