roomabuzzy

So I did a search for clutch squeal noise and the only good answer I found was talking about the TO bearing being kaput.. but I don't think that's the case with me, and here's why...

A little history (88 90Q BTW)... I know my clutch is very bad, needs to be changed.. 2 days ago, got caught in a bit of traffic so I had to play with the clutch a bit. all of a sudden, I see a little puff of smoke come out of my engine near the rad area and my dash lights up the Engine Coolant light (high temp or low fluid level). Temp was perfect and when I stopped to check, coolant is full. The light turned off after a few seconds and hasn't come on since, also, no smoke since then either. But since then, the clutch has been squealing everytime I press it in even only slightly. Now, it's even louder (very embarrassing) and it's getting hard to shift gears.

I'm thinking master/slave or pierce in the line somewhere (since my brake fluid seems to be going down but it's hard to tell... if it's going down, it's REAL slow).... but anyways, I've never worked with a hydraulic clutch before, so I would appreciate some guidance.

Evidentally, I know the first answer I would usually get is to pull things apart and check, but I'm going to be doing the clutch in about 2 weeks, so I'd like to order whatever I need to fix this problem before hand if possible so I don't have to keep the car off the road for god knows how long (and I might not have access to a hoist for long).

So basically, if there's an obvious problem that can be found using what I've described, or if there's something that's prone to fail on these models that I'm not aware of, please let me know. I've consulted the Bentley, but again my lack of knowledge in hydraulic clutches in my downfall. Any help is appreciated so I can figure this out before I take the tranny down. TIA!

dtompsett

Basically, there is a master cylinder mounted in the car (or to the firewall), and a slave cylinder mounted to the transmission.

Push down on the clutch pedal, it pushes in a hydraulic cylinder on the master cylinder... forcing fluid through the flex line... into the chamber in the slave cylinder... which forces out a hydraulic cylinder to push on the clutch release arm... pushing the TO bearing into the clutch fingers, causing the pressure plate to release.

Areas that can fail in the hydraulic system...
-seals on the master can go bad (usually results in a leak into the interior of the car. If you've got the map pocket still under the dash, pull it so you can see pedal linkages. Look for signs of seepage from the clutch area.)
-hard line can rust out and spring a leak (I'll describe my experience below)
-flex line can burst (just like bursting a flex line on the brakes)
-seals on the slave can go bad (usually results in brake fluid leaking into the bellhousing of the transmission. Possible contamination of the clutch friction surface may result)

I had a hard line rust out last christmas. Started getting harder and harder to get into gear... less and less travel to the pedal. Then it just went to the floor (no resistance) and I was stuck without a clutch. Drove 200km of county roads with traffic lights and small towns the whole way home. These cars have a starter with lots of torque... but not much RPM... so they don't like to start when you put it in first and crank on the starter. Clutchless shifted as much as I could, coasted up to red lights, and worst case, popped into neutral, came to a stop, shut the engine off, put it into 1st, and cranked the starter till it kicked over again.

My flexline was fine (well... cracked and old... but not leaking). The hardline had failed from corrosion. Rather than buy a new one from Audi ($$$$), I salvaged the fittings, went to the local parts store, had them let me go through their collection of brake lines till I found one with the right ends that I could use adaptors and flare some fittings to new line. Made my own hard line and flex hose!


So, go looking for the leak. It's either in the car at the pedal, in the transmission at the slave, or along the line connecting them.

If you have to replace the slave, also do the master... since they're likely to go at the same time.


I'd be curious if the puff of smoke was related to the cooling system, or to the clutch. Might be a leaky slave spraying fluid on a hot clutch... but wouldn't explain the coolant warning light.

roomabuzzy

ya I found it quite strange too how the coolant light and the puff of smoke came at the same time. That's what really puzzled me.

My experience is a little different that yours though. Clutch pedal isn't getting any easier (I'm guessing the feeling would be similar to that of a brake pedal when you're out of fluid).. in fact, it seems to be getting harder to push (could be my imagination though from all the frustration... but it certainly isn't getting easier). Also, I'm still curious as to where that squealing sound is from? It could be the TO bearing as it was mentioned in another post when I searched the archives, but the sound started at the same time as my problem, so I would assume it's related. Could some kind of leak in the hydraulic system cause this squealing sound?

Also, do you remember the size of the fittings for the line?

AudiSport4000

It only makes the noise when you push the clutch pedal in, correct? Do you feel any pulsation in the pedal?

roomabuzzy

I've felt pulsation in my pedal for a while now, but the squealing just started recently.. but yes, it's only when I push the pedal in.

AudiSport4000

Sounds like its time for a clutch overhaul.

roomabuzzy

car has approx. 276,600Kms on it, and yes, I'm changing the clutch in a couple of weeks.

AudiSport4000

Clutch jobs are always fun :P