Wondering if anyone out there has any idea what might be going on with my clutch. I've got a 97 A4 Quattro with 160,000 miles on the body, and about 60,000 on the engine. Basically whats happening is every once in a while, my clutch sticks to the floor. I'll push the clutch in to start the car, or put it in to shift while I'm driving, and it won't come back out. It seems that if I just keep tinkering with things for five or ten minutes (mostly just pushing and pulling on the clutch pedal with my hand), it'll go back to normal, and work perfectly for another week or two till it happens again. When it happens, I can pull it back out with my toe or my hand, but then it takes very little pressure to push it back to the floor, where it'll stick again. While it's in this state, it's not actually engaging the clutch (I can't put it in gear). I know that it's a hydraulic system, and I'm wondering if one of the cylinders is on it's way out. I also thought that there might be air in the lines, and I know there is a bleeder valve for the clutch system somewhere, but I haven't tried bleeding the system yet. I can't figure out how air would've gotten in, I've got plenty of oil left in the reservoir. I'm thinking that it's probably the slave cylinder, because the master cylinder (behind the pedal) goes in and out smoothly. The funny thing is that it never works half way, it'll either work perfectly or not at all, and once it starts working again, it seems to work well for a while. Any ideas? Thanks.

 

Sounds like the clutch slave cylinder. They fail occassionally.
They do have a small bleed valve on top of them, and you can bleed it just like bleeding your brakes.