Maybe this will help explain what I'm trying to convey here Joe?
*Remove the apply pin & cushion spring from the piston.
*Install the piston in the case all the way to bottom.
*Measure & record the depth with a dial caliper. (Mark the point on the Case where your taking the measurement as the the bore is machined at a angle)
*Install the Apply Pin back into the Piston with the Washer & E-Clip. Leave the Cushion Spring & Spring Seat off for this test!
*Install the Piston back in the case along with your test tool, Tighten the check bolt to 55 inch pounds.
*Force the Piston down against the Washer.
*Take another Piston depth measurement at the same spot as before.
Subtract the two readings from each other......This will give you exactly how much piston travel you have before the Piston bottoms out against the case.