<VV> Pressure plate pressure

[Smitty]

Smitty Says:   I can't help you with how much pressure is required to 
depress a diaphragm.  I had the same interest a few years ago and did some 
experimenting. Sorry I have forgotten what the required pressure is.  One 
number I still have is the thickness of a pressure plate disc measuring from 
the ridge that the fingers pivot on to the ground surface of the plate on 
the other side.  These things have been around for years and no telling how 
many times they have been ground.  Of course clutch bite is reduced every 
time it is ground thinner.  That dimension is 7/8 of an inch for a new one. 
I have found some that measured only a little over 3/4 inch