Hi everyone I have a 1965 c10 with a lt1 and t56 out of a 97 camero recently I’ve developed a issue where clutch pedal pressed fully to the floor it doesn’t disengage but 20% pedal pressed it will only happens every now and then and I can’t seem to find anything about it I have no leaks and plenty of fluid. When the truck is started in gear clutch to the floor it smokes the clutch, with the truck on a hill in gear(my driveway) clutch to the floor it doesn’t roll but 20% of pedal it rolls what’s my issue, thanks you for your time

 

Try a new Master Cyl.

 

+1 Pressure could be leaking internally within the M/C at the different points of travel.

Do you have to let the pedal out and press it again for the problem to correct and the 20% press to work again? Or can you go from full-down to 20% and have the clutch disengage?

 

Are either or both the master and the slave adjustable? If so you could have the adjustments way off.

And did you measure and shim the slave if necessary?