So here's the story: I have a'49 3100 that I am trying to convert to power brakes. I installed a braket kit from CPP with the recomended Mustang master cylinder & booster. I also installed the 1/2 " extension to the pedal linkage. I am using the stock pedal with the under cab mounting along with the stock 11" drums front & rear. I did install a 10 # check valve in the m/c since the m/c is for a disc / drum combo. Now the problem. The pedal goes down about 4" before the brakes engage. Ive got the brakes adjusted to a slight drag, the system has been vaccume bled etc. I'm at a loss to solve this problem. Any ideas ???? Thanks.
Make sure you have a 1/16 " freeplay in the pushrod to booster no more. Second if you are using the stock non-power pedal ratio you will have excessive pedal travel, PBs use ratios around 4-1 manual brakes 6+-1 .
Things I would check: If the master is for a disk/drum setup, that might be your issue. What is the pedal ratio? The lnkage may not be moving enough. Are the drum brakes adjusted? What was the original master bore vs the mustang bore? Is there slop between the master and booster?
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