How can you tell if your booster and master cylinder are working properly? I have installed a front power disc conversion kit on my 69 and regular drum on the back. I have replaced all brake lines, booster and master cylinder as well as the proportioning valve. I have been unable to get fluid to flow to the rear and front brakes. Could it be that the booster and master cylinder are not working properly or could it be the proportioning valve? What could be stopping the lines to prevent the fluid from flowing? I have bench bled the master cylinder.

Do you feel any resistance in the pedal? Is the pushrod in place?

There is a little resistance, but the pedal goes straight to the floor. The push rod is in place. I'm using a bleeder and am finally starting to get some brake fluid to the rear brakes, but there are a lot of air bubbles. I still can't figure out if my master cylinder or booster are working. Thanks.

It just hit me. I think it is your soft lines on the rear. I had to change mine when I did the 4 wheel disc swap cause the hose would collapse.