What gives? I just installed a new clutch, pressure plate and throw out bearing in my 85 GT. I've put about a thousand miles on it with no problems until today. The clutch is not disengaging, and the clutch pedal is very stiff. I checked th slave cylinder and it seems to be working fine. The clutch was a CarQuest factory replacement. Any ideas? I dread having to drop the cradle again.

Sound like the springs in the clutch disc has collapsed and you have to drop the tranny any way have fun.

OR... if you had the old style, welded together clutch fork, it fell apart...like mine did.

Dropping the tranny is a fairly involved process, so before that avenue is explored I would like to ask you the following...
Did You see if the shaft that protrudes out of the slave cylinder moves about 3/4 to 1 inch when depressed(by having someone press the pedal while you check the shaft)? If this distance is traveled by the shaft then I am afraid that the clutch hydraulics are working properly and something else has gone awry(tranny removal time).