Clutch Master Slave Cylinder Question

[joyridin']

Just to make sure you have all this set-up correctly:

Nearly every clutch master cylinder is matched for size to its connected slave cylinder for a 1-to-1 relationship. So, a 3/4" bore master cylinder should only connect to a 3/4" slave cylinder. A 1" master should have a 1" slave cylinder. A master cylinder that is larger will yield a rather spectacularly blown out slave cylinder and a master cylinder that is smaller will yield a rather disappointing lack of travel for your left foot's efforts.

The pressure plate must move about .100 to .120 of an inch to RELEASE THE DISC and provide .030 to .050 air gap between the disc and the flywheel.

A 9" clutch has about a 4.5-to-1 arm or diaphragm ratio.
A 10.5" clutch has about a 6-to-1 arm or diaphragm ratio.
An 11" clutch has about a 6.6-to-1 arm or diaphragm ratio.

The release bearing must move away from the fingers or diaphragm sping at least 1/16"
(.0625 rounded off to .06) for freeplay.

The release fork ratio is determined as described in the release fork section.

Example: A 10.5" clutch and a #RAGM GM release arm (2.17 ratio).

So, 0.120" required movement multiplied by the ratio of a 10.5" clutch equals .72" plus .06" movement of release bearing for freeplay equals .78 of an inch. Multiply .78" by the ratio of the release fork (2.17") equals 1.69" (or 1-11/16") of travel required where the linkage attaches. It doesn't matter if the linkage is mechanical, cable, or hydraulic, it must be able to move the end of this arm with this pressure plate the above indicated amount in order to properly release the clutch disc.

For comparison, using the same release arm with a 9" clutch only requires about 1-5/16" movement while the 11" clutch requires almost 1-7/8" of movement -- nearly 9/16" more. It is the ratio of the pressure plate that makes this difference.