Clutch Pedal

[Mike Arman]

>From: "Paul R Luevano" <prl at ptc.com>
>Organization: PTC
>To: 200TQ20V List <200q20v at audifans.com>
>CC: Quattro List <quattro at audifans.com>
>Subject: Clutch Pedal
>
>Well, it did it to me again.  Last night, I was leaving downtown Boston,
>and the clutch pedal went to the floor. 

snip
>On the way home, the pedal came back, fully functional.  Ok.  Then this
>am, went right to the floor again.  I checked the brake fluid reservoir,
>it was a tad low, so I topped it off, but it didn't seem to help.
>
>Now, this happened to me this summer as well, but after topping off the
>brake fluid it was fine until now.  I suspect I have a leaking slave
>cylinder.  I top off the fluid, it comes back for a while until air
>enters the system again.  Sound likely?  


yes.

>
>I'm guessing my only real course of action is to replace the slave
>cylinder, but from what I have heard, that is a major, major PITA. 



Not really too bad - there's a retainer spring which comes off, then you
jack the car WAY up on the right front, take off the RF wheel, and work
through the fender well. Stack 3/8" extensions until you have a drift
almost two feet long. Put a punch in the end, and use this to drive out the
roll pin holding the slave cylinder into the bell housing. It *is* a PITA,
but not too bad, especially the second time.

Takes some fairly strange yoga positions to get it all back together, and
you'll be sore tomorrow. It is also easy to break off the radiator neck by
lying across it (don't ask!).

When done, bleed the system. It helps to pre-fill the slave cylidner before
installing it. Messy job, BTW.


 I
>would also like to make sure that is the problem, before I tackle the
>job.  
>
>Are there any checks or test I can perform to make sure it is the slave
>cylinder?  Are there any other likely culprits?
>
><Insert lunch>
>
>Went out and checked it again, there is a puddle of brake fluid
>underneath the car.  I topped it off and ran some errands.  the clutch
>fluctuated from completely useless to 100% functional.
>
>I'm guessing that is it time for a new slave cylinder, since if I look
>at the bell housing from the engine compartment, I can see that it is
>wet.
>
>I looked over Chris Miller's page, and the following paragraph confuses
>me:
>
>"Symptoms: in my case the major symptom was the excessive use of clutch
>fluid.  As the master cylinder is located in the pedal box on the inside
>of the bell housing, it is a easy matter to check where the fluid is
>leaking.  No obvious leaks means that the slave cylinder (which would
>leak into the bell housing) is the culprit. "
>

If it leaks onto your foot, it is the master cylinder. If it leaks onto the
ground, it is the slave.

Check your left shoe: If you wear leather shoes and find yourself shining
the left one much too often, it is the master (it drips onto your shoe and
removes the polish!).

R&R master needs a 6mm allen wrench with the short leg cut even shorter for
clearance. It is also a little tricky to replace the circlip on the end of
the clevis pin, but can be done with some creative cussing. It helps if
you're not a BIG guy (6'6", 350 lbs) when you do this job. There's also a
pushrod length adjustment to check!


Warning: rebuilding these cylinders is not generally successful, even
though you can get the parts kit cheaply. On no account use DOT3 brake
fluid! It will go right through the seals, ruining them at once. Use ONLY
DOT4 here. I seem to recall spending under $150 for both the slave and the
master from one of the approved Audi list vendors last time I did this job.

Best Regards,

Mike Arman