I have a 1995 Infiniti G20. I was driving and everything was fine when my clutch went straight to the floor. It was incredibly arduous to pull back up, now the clutch is very stiff, almost impossible to push down. What could the problem be?
My guess is your slave cyliinder in the transmission is going bad. That happened on my jeep but it never got hard to push, it just slowly lost pressure until the pedal would not rebound from the down stroke.
Change both the master and slave cylinders as a set. Their seals’ life expectancies are pretty close. If one’s passing fluid, the other will be soon.
I think the problem is the pressure plate, not in the hydraulics. Time for a new clutch kit.