Reply to "missing pressure build up in brake system"

quote:

The casting number on the master cyl decodes to a Ford truck, most likely a Ranger (1983-1985). Replacement cylinders are steel, not aluminum.

Bore size: .9375" (15/16")

Line thread size: 9/16-18, 7/16-24 (power brakes), NAPA #M2481

Line thread size: 1/2-20, 3/8-24 (manual brakes), NAPA #M2482

The bore size of the stock Pantera master cyl is .875" (7/8")


The Ford Ranger has front disc and rear drum brakes. Typically, drum brakes have a residual check valve (in the master cyl), and disc brakes do not. Since I have never had one of those Pantera vendor supplied Ford masters to disassemble, I don't know if the Pantera vendor removed the residual check or not. It's easy to remove.

If you choose to go to a 1" bore master cyl, a master from a 1986 Ford F150 should work, but the hard lines are on the opposite side from the one that you have now.

Bore size: 1"

Line thread size: 9/16-18, 7/16-24 (power brakes), NAPA #M2405

Line thread size: 1/2-20, 7/16-24 (manual brakes), NAPA #M2408


If you decide to change your master cyl, you can mic your existing tubing nuts to determine the line thread size that you have, and then go shopping. Master cyl tubing nut adapters are readily available if you have to change size(s).

All of the above sizes were pulled from the NAPA website. YMMV