Clutch Problem - HELP!

[rbrack]

I have a 2002 Boxster S with about 90,000 miles. About two months ago I was driving and all of the sudden the clutch pedal started vibrating. It no longer was as stiff, and only came up about halfway from the floor. The clutch hadn't been slipping, and even after this happened, it still didn't slip. When the engine was powered off, the clutch pedal would sit on the floor. After starting the motor, the clutch pedal would build some pressure and rise partially. I was in the process of moving at the time, so I trailered it to my new home and started working on it a few weeks ago. I've replaced the clutch master cylinder and slave cylinder, bled the system, but the clutch is still acting up. Now, the clutch pedal stays mostly out, but still doesn't feel as firm, and it still vibrates when the car is running. It feels fine when the engine is off. I haven't driven it yet, as I am scared that something else is still wrong. I'm afraid that the clutch needs to be replaced, especially considering the mileage. Any ideas?

Edited September 24, 2010 by rbrack

[RFM]

Good chance that the pressure plate is cracked, you will need to build out the gearbox to have a better view on the problem.

[JFP in PA]

If you still have the original clutch, it is well past its expected life (usually gone in 40-60K miles), so you shouldn't be surprised. Time to pull the gearbox and renew the clutch and flyhwheel units; also a great opportunity for an updated RMS and IMS, as you need to pull the clutch and flywheel to get at them.................

[rbrack]

Ok, pulled the tranny the other day. The clutch and pressure plate are fine (although the clutch disk is quite worn and needs to be replaced). The only thing I could find actually wrong is the flywheel; it doesn't rebound when twisted. The rubber-looking material in between the two parts of the flywheel is just about gone. The other thing I found was that the throw-out bearing was almost completely rusted to the guide tube. The pressure plate looks fine; no cracks, no damage of any kind. Would the flywheel cause the chatter in the clutch pedal, or do I need to look for another problem?