I'll try to get all the details in and be as specific as possible:

2000 LS1 motor/T56 trans. Brand new updated GM slave. New aftermarket master cylinder. The master cylinder side of the line has been cut and extended with a new fitting for the aftermarket master. The drivetrain is in an RX7.

Under normal driving the clutch feels good and and has no problems. But...

If I take the car out of gear, rev the motor, and slowly let the clutch back out, the next time I press the clutch it will feel very stiff and will not disengage at all. If I push the pedal another time or 2, it will disengage and return to normal. I can reproduce this scenario consistently.

Also, if I try to quickly downshift and accelerate from second/third grear, the clutch will sometimes (not always) continue slipping for a short time after the pedal is released and then the same situation with the stiff clutch occurs as described above.

I've bled the clutch using several bottle of fluid, using the hold clutch, open bleeder, close bleeder, release method, with a hose attached to the bleeder and the other end in the jar. I am fairly confident there is no air in the line. It seems like air would not cause the clutch to feel very stiff and not disengage at the same time.

When the issue occurs it seems as if something is stuck somewhere that will not allow the clutch to move where it should. I am not sure how slipping the clutch under load would cause this to occur when at all other times everything is fine.

Any ideas?

Thanks,
Jeff

 

The theory I have with my personal clutch issues is that the cylinder cup is getting jammed. I reach that conclusion because lifting my pedal veerrrry slowly allows a firm pedal for the next stroke (often, but not always). I am going to blow another weekend on mine taking out the master and re-honing the cylinder.