TEF1701

I discovered my first problem with the Special Build 87 CGT I inherited. The clutch pedal randomly fails to go back up. My uncle had the same problem, so he tied a strap to the pedal to pull it back up. He thinks it's a return spring on the pedal, but it doesn't happen all the time. Any thoughts on what could cause this? I don't have a repair manual yet, so I'm flying blind. I don't even know if the clutch system is hydraulic or mechanical.

AudiCoupeGT1986

Clutch is hydraulic I'm pretty sure. Perhaps its air in the lines?

Rogviler

My '84 CGT had a mechanical clutch, but I think they switched circa the facelift. It would be easy to tell: A mechanical one will have a linkage from the clutch pedal directly to the driver side of the transmission. A hydraulic one will have a clutch master cylinder attached to the pedal on the engine side of the firewall, and there would be a line from the brake reservoir dedicated to the clutch. The slave cylinder is right under where the tie rods connect above the transmission (see my link below)...

I'm guessing it's hydraulic because it sounds like a bad slave. Usually the little rod that pushes against the throwout bearing can get worn or even break, and the seals can fail as well.

I detailed my experience in replacing mine here:

https://www.audiworld.com/forums/sho...8&postcount=21

Basically, it would be a pain in the butt to do it with the engine and transmission in the car. Obviously you're better off pulling the transmission than the engine, and it will certainly make it easier to get the slave out and back in (guarantee it will be stuck in there).

Something I didn't mention is that when you put the new slave in it'll need to be bled and there's no way you'll ever be able to do it with the pedal pump method and many people have said that even a power bleeder won't do it. The solution that I just learned is to get a small pump oil can at your local parts or hardware store and fill it with brake fluid (don't use it for anything else). Then attach a piece of tubing with an inside diameter that will fit over the bleeder valve on the slave. All you have to do is open the bleeder valve, attach the oil can, and then fill the line until no more bubbles come up inside the brake reservoir.

It's also a good idea to replace the clutch master at the same time, and while you're at it check the firewall where it attaches for cracks (repair as necessary).

Of course if you have a mechanical clutch or it's not the slave then disregard the above.

I don't think there's any kind of spring on the pedal... When I was having my issue it wouldn't come back up a lot of the time. Replacing the slave got the pedal working correctly again. But double check under the dash, it won't be hard to see.

I wish I could tell you a good way to diagnose it, but basically between the pedal and the clutch there isn't a whole lot else to go wrong and the slave will go out at some point.

To rule out air in the lines, just use the oil can fill method above and see if it improves at all.

-Rog

TEF1701

So..... if i understand you correctly, I need one of those old style pump-type oil cans? I then use that to force the fluid backwards through the slave cylinder, into the master cylinder, and up into the reservoir? If that's what your talking about, that is genius!!! I didn't have a chance to look at it today, but I will check it tomorrow. Thanks Rog! I had a feeling it was either the slave or the master.

Rogviler

Yeah, and all this time I thought it took hundreds of dollars worth of equipment and or a whole weekend of work to do it right...

This is the one I found at O'Reilly for like $4:

http://www.amazon.com/OEM-Ounce-Pump.../dp/B004FELML8

I just used a large diameter piece of rubber hose to connect it to some vacuum line that fit over the bleed valve.

Another thing that helps is to put a tiny bit of teflon tape on the threads of the bleed valve. That keeps fluid and air from leaking through the threads. Same with the brakes the next time you have to bleed those...

-Rog