Tom. M

I had an issue in my GT when the clutch master cylinder didn't come up enough to allow fresh fluid from the reservoir make it into the system.. effectively locking what fluid was in the line between the master and slave. Clutch started slipping when the fluid heated up..and it had nowhere to go but to push on the slave ever so slightly....which let the disc slip under load. Bled the master from the inside (and removed the washer on top of the cylinder) to allow the fluid to move freely...haven't had a problem since...and the old disc I replaced...is still sitting at the shop awaiting the time I actually wear out the one in there..

GregBBRD

Sorry. Don't want to argue....and you can believe whatever you choose to believe.

However....this is pretty simple mechanics, logic, and physics.

The only thing the hydraulic system does is release the clutch. Anything that causes to hydraulic system to not work fully (except the pushrod being too long (which causes the master to not return fully) will not cause the clutch to slip. It will cause the clutch to not disengage completely. You can go out and cut the line to the hydraulic release system and the clutch won't slip, because of this.

You might have had some oil on the disc, or the T/O bearing or the T/O arm might have "caught" on something...making the clutch not fully disengage...but bleeding the clutch will never help a slipping clutch.

You might as well have gone out and peed on the side of the car.

Courtshark

Sure sounds like an argument to me. I think we're perhaps miscommunicating. What we experienced was not "clutch slip" but more likely a failure to disengage completely. It feels about the same as a slipping clutch, though. Semantics among mechanics.

GregBBRD

Yes.

Exactly what I said...with the words "switched around".
Pushrod or master doesn't return will not allow clutch to completely release. Takes 10 seconds (tops) to determine this. If you can't feel free play between the master and the pushrod, you need to find out what is wrong and fix that, first! If in doubt, bend down and look at the pushrod and make sure there is play between the pushrod and the master!!! Something can go wrong with the pedal return mechanism, something can go wrong with the pushrod.

Bleeding, alone, isn't going to fix that.

In your case, you had some sort of a blockage that kept the piston from returning?? There's a whole bunch of hydraulic pressure trying to return that piston. Tough to imagine some restriction in the 8mm ID free flowing return hose that will keep pressure in the hydraulic system.

Sad you had to remove the clutch and disc to figure this out.

I'm trying to keep the OP from making this mistake.

GregBBRD

OK.

No "skin" off of my back.

Word it anyway you want to. Write it in French, if it makes you all feel better.

For the clutch to slip from a hydraulic problem, the only thing that will allow this to happen is for the master to not completely return! This is a mechanical problem, not a hydraulic problem! It takes seconds to determine this! Literally seconds! Bleeding will not cure this problem!!!!

You "mechanics" have fun!

Courtshark

1) My car demonstrated clutch slippage-like problems only when warm; in 3rd - 5th gear, at cruising at 50 mph plus, get on the gas and the car would not accelerate, or not as quickly as usual.

2) I bled the clutch.

3) The slippage-like problems went away. Instantly. And have stayed away for about 1k miles since.

Perhaps something in the bleeding process positively affected something mechanical that was not working properly. I honestly don't know. But bleeding the clutch somehow fixed the problem. Hard to disagree with such direct a real world cause and effect. And definitely no reason to go all bold and wacky colors and stuff. Will the next one be all caps? And maybe in purple?

It's not like bleeding the clutch is some kind of monumental task, either. If it works, awesome. If not, no big deal.

GuardsRedHammerhead

Wow, I take a long lunch and come back to quite the debate.

I am prepping right now, for a clutch kit. I want to see what is going on in there, anyway. Wish me luck.

I do not have an "X" pipe. Do most of you find that you have to drop the exhaust to do the job? Is it as simple as 6 bolts to get that housing cover off?

GuardsRedHammerhead

Regardless of the debate behind this thread, I thank each and every one of your for your advice and experience. I have only ever done the clutches on my 951's, and they were certainly harder than this is going to be.

I am glad to have the Rennlist brothers to go to for wise counsel. Thanks again, all.

hacker-pschorr

I would rather pull my clutch pack and inspect all the mechnaical parts before I just bleed the system for a problem not normally associated with a hydraulic issue.

Screwing up a clutch bleed can intorduce more problems.

I can just picture Greg having this conversation, in person, at his shop. At some point while the customer is further explaining things to Greg, he walks over to the bench, picks up a big hammer and starts to beat his own head with it.

yak 944s

For my clutch replacement on my 87 S4 it was easier to drop entire exhaust. There are 2 bell housing bolts behind the exhaust that are pretty much inaccessible unless you remove the cat pipes or entire ex system.

AO

Not a bleeding problem IMO. If it slips in the higher gears it's because the mechanical leverage in those gears able to overcome the grip of the clutch (if that makes sense). Could be because of clutch wear, mechanical problem, or oil on the clutch.

Sorry...

GregBBRD

I quit beating my head years ago. Just makes my head hurt and doesn't change the opinion of the idiot standing there. I do listen carefully for little details about what is wrong...these are of great importance and genuinely help me figure out what is wrong. However, when they start to tell me what exactly the problem is and how to fix it.... I just listen and try not to react. Once they leave, I go out and figure it out.

Here's a great story about the very last time I let a customer diagnosis something for me.

Customer came in with a "roaring" noise in the rear of his 914 (the fact that it was a 914 should give you a clue about how long ago this happened.) I drove the car and told him I thought it was tire noise (the tires had "cupped" sections on the tread.) "No", he insisted. "Had to be a rear wheel bearing". Told me to replace the wheel bearings.

I gave him a price and replaced the wheel bearings...which looked fine, BTW. The noise was still present.

Called the customer, telling him the noise was the same and that I thought the noise was the rear tires.

"No" can't be the tires. Told me the problem had to be in the rear axles and wanted me to disassemble, inspect, and re-pack.

Gave him the price to do this, and reluctantly did this.

Guess what? The noise was still the same.

Called the customer and told him the noise was still the same. "Well, you missed something in the rear axles. Replace them with new."

Well...gave him a price and replaced the axles with new. Noise still the same.

Called the customer and told him the noise was still the same, now virtually insisting that the noise was the rear tires.

"No, not possible. too loud. Has to be inside the gearbox". Insisted I rebuild the gearbox!!!!

Well, gave him a price. Took the gearbox apart and replaced every bearing in there. Put in new "syncros", etc. Of course, when done, the noise was still there....

Now, smart enough to know that this customer wasn't going to like the fact that the noise was still there and would want me to start redoing work, I took off the rear tires and "attacked" the "cups" on the tires with a belt sander.

Noise gone. Gone!

Called the customer and told him the noise was gone....and told him that his rear tires were getting thin and he should replace them, soon.

This is an honest to god story! Happened here!

What did I learn?

The customer might always be right, but sometimes you need to fix what is really wrong....even if you don't tell them.

Heh....you guys can go bleed your clutches to your heart's content, to "fix" your slipping clutch. But once you stop and learn how and what the hydraulic system is actually doing, unless the master cylinder doesn't have "freeplay" for some reason (which takes one push on the pedal to determine)...the hydraulic sytem isn't/can't possibly be the problem.

You might as well go out and "rotate" your lug nuts.

Courtshark

Not to beat the dead horse, but what explains that this only happened when the car was warm?

GregBBRD

The horse should be completely dead.....and buried.....deep.

I don't see where the OP said anything about only slipping when the car was warm.

If this is in reference to your clutch slipping "issue", I have no idea....but bleeding the clutch hydraulic system isn't what fixed it....unless there was some mechanical thing keeping the master cylinder from returning to its stop which the sheer movement of the clutch pedal, during bleeding, corrected.

Courtshark

No need to be a jerk, Greg. I asked an honest question. This is an online forum. For questions. If you don't like them, don't answer them. And you still have not, in case you were trying. I guess youre not omnipotent.