I have a 1972 F250 4x4 with four wheel drum brakes that I have tried to convert to power brakes. I have put a new brake booster and master cylinder on and also wheel cylinders but the pedel still goes to the floor. I have changed out the master cylinder twice and I am getting ready to change the front brake hoses. Any ideas or help on what else may be wrong? Thanks!

 

I'm not a 100% sure if this is your problem, but I know the brake lines are different for power brakes vs. manual brakes. I would look into that. You may need to change the lines.

 

proportioning valve ?

 

I have not heard anything about the brake lines but I will look into it. The proportioning valve did cross my mind. I am changing out some of the brake lines and the front hoses today so I might take it off and take a closer look at it and clean it up. Thanks!

 

does anyone know what the difference is on the brake lines when switching from manual to power?

 

You do not need a proportioning valve if retaining four wheel drum brakes. Make sure master cyl is correct (MC39468 is Raybestos part #), also make sure pushrod length is correct.