Yeah I have done a bunch of research on the conversion and here is what I came up with:
The stock (Single cylinder) Jeep master cylinder will work, however you need to remove the residual check valve or replace it with a lower pressure one, as the disk breaks do not need it. The check valve retains some pressure in drum brake cylinders so that they need less fluid to activate them. This being the case I don�t think you can do front discs and rear drums with the stock cylinder, however if you went to a dual master cylinder you can do it as you retain the check valve for the rear brakes. The other thing you need is a proportioning valve in the line to the rear brakes. That is so you can properly balance the brakes because the fronts do 60% of the breaking and you do not want the rears locking before the fronts. I am thinking about doing all 4 in the spring, and will keep my stock cylinder.
