Fordman,fordman wrote:did you put on a proportion valve? you have to have that valve with front disc and rear drum brakes.
for the brakes to work you don't have to have that proportion valve... I converted my Mustang from Drum - Drum to Disc - Drum and have never installed this... Yes, it will change your braking bias from front to back but only by a relatively small percentage... You would feel this more when stopping on a truck that is light in the rear but you will not feel the difference in the pedal just working the brakes. The brakes should still work like normal / pedal feel like normal... fluid flow and pressure is still a constant thing (relatively speaking)
His problem is that the pedal goes to the floor but he can pump it up some but it goes away, yet he checked the master with the lines blocked and it worked fine so the master sounds like it is good. He is loosing pressure / fluid volume somewhere (more then likely air trapped in the system...)
One other thing that would do this is if the front and/or rear brakes were out of adjustment far enough that the pistons wont push out far enough on one stroke of the master cylinder to apply pressure to the disc / drum. This is more of an issue with drums then with discs…
I hope this makes sense on the proportion valve...
Glad you got them working! and this place is addictive 
