clutch master, how many psi?

[RoverP480]

Going back to the pressure in the fluid, one could work it out. Measure the pressure on the pedal to release the clutch ( in lbs) , multiply it by the pedal ratio to the master cylinder push rod and divide by the area of the master cylinder piston area, in square inches.

[COLVERT]

Originally Posted by roverbarmy

Wow! High pressure indeed! Which leads me to believe that my theory of the failure of the Taz* metal cylinders was due to the failure of the seals between the brass cylinder liner and the outer alloy casing. They were tiny, circular section seals (similar to watch caseback seals) . That sort of pressure would eventually force fluid past them and out via the pushrod end. If they had been pressure seals (ie tapered profile) the pressure would force the seal into the outer wall to retain the fluid, rather than seep past it.

Those circular section seals do look rather small and maybe that's the problem.

Some cars have wheel slave cylinders with circular seals and they work very well. I had a Fiat with them on. Under pressure the circular section becomes oval and is forced OUTWARDS to seal harder and harder against the cylinder walls.---