94 LS teggy. New clutch, pressure place, bearing, and slave cylinder. Every now and then the clutch pedal feels as if it takes 3 times the regular pressure to push the pedal down and then the clutch doesnt grip at all, sometimes it will only drive if i barely accelerate and if i give it alot of gas the clutch will slip terribly. There is no leaks in the line the only thing i can think of is the master cylinder. Also when the clutch acts up and i bleed the system it will work excellent and not have any problems for a few hours then it will start slipping again and not grip the way its capable of doing. When it works well it will catch at prety much any RPM then it screws up slips real bad. Could this be the master cylinder? The lines are perfectly intact and the master cylinder is the only thing i havent replaced yet

 

The master and slave cylinder wear EQUALLY. So by changing just one without the other is for sure going to cause you a problem.