Hey guys,
I recently bought a well maintained and adult enthusiast owned 2004 A4 UltraSport 1.8T 6 Speed stock (except for exhaust and suspension) with 133k on it. This is my first Audi. The car has been mechanically perfect with no signs of clutch issues until this past Thursday. I was shifting quickly from 2nd to 3rd and the car would not go into 3rd. I tried other gears with no luck and when I lifted my foot off the clutch it stayed on the floor. When I pulled over I was able to build clutch pressure back up by pumping it, which to me made it seem like a hydraulic issue. I was able to get the car in first but it made a grinding noise when I tried to pull forward. The next time I tried to get in gear it would not go. I can hear the revs drop when I try to get in any gears indicating that all syncros are working. When I bled the slave cylinder it squirted fluid in a seemingly strong stream. I replaced the slave cylinder (with a Perfection clutch that was made of cast aluminum unlike the plastic OEM Sachs unit) and when I built pressure back up it hit a hard point halfway down. Fearing that I had missed the clutch fork with the slave piston I removed and reinstalled the slave, this time the slave leaked from the hard line fitting when I tried to bleed the system. I bought another slave, and this one was a plastic OEM-style Sachs unit. Now I can't build any pressure to save my life. I'm wondering if I again botched the installation, and if my original problem was never the slave at all. Could it be the clutch master cylinder? Throwout bearing? Clutch fork? I'm starting to see a dropped trans in my future.
Thanks

 

Bleeding the clutch system on these things is tough. You just about have to pressure bleed them. BUT.. It can be done. I'd get one of the those one-man bleeder bottles (they are cheap but handy as heck for bleeding things) and give that a whirl. You'll basically put the one-man bleeder (it's a little bottle with fitting at the top and a short section of hose inside to help prevent sucking air back into the system when there's some fluid in it) and operate the clutch pedal (by hand) a few times to pump fluid down to the slave cylinder. Once you've done a couple or three pumps (be sure to fill the fluid reservoir to the max as sucking air in from the top will defeat the purpose) quickly close off the bleeder on the slave cylinder. Check for pedal. Keep adding fluid and bleeding until you get it.

Also, a rule of thumb I go by is if I have to replace either the clutch master or slave cylinder, I'll replace both at the same time. There's not a lot of fluid in those systems and the way it operates makes is more likely that trash that may be in the slave cylinder will get sucked back into the master cylinder also.

 

Reinstalled the slave, and gravity bled the system. Seems to have good pressure when the slave was held with a C-clamp. When the slave is in the trans it's building pressure but it seems to not be pushing on anything. Gonna try to drop the trans this weekend and see if the fork got bent or the clutch assembly failed somehow. Already ordered a Valeo single mass flywheel (22.5 lb) clutch kit from ECS. Seems like if anything went wrong with the clutch, all that damping in the stock dual mass assembly would explain why I didn't really feel or hear anything. Bought a clutch fork while I was on ECS in case that's what broke. Wish me luck!

 

Yeah, it does kind of sound like something has failed in the bell housing or is stuck. Check the throwout bearing slide collar too. I'd replace it if it doesn't come with the clutch kit.

 

Hey. Man whats the end of the story because i have similar problem on my a4 b6 6sp manual pedal is working but not doing enough pressure. What turned to be in ur case?