power brake problems

i need some advice. i just rebuilt my brake system, it came factory with power disk in front, i have replaced rotors, calipers, shoes, brake lines, master cylinder, had the prop valve rebuilt, the problem i am having is the back brakes will not lock up, it feels like i have no power brakes. i have bled the lines, have good vacumm, i never had the opportunity to drive the car before i rebuilt the brakes, so how should they react? could i have a faulty new component? where do i start? thanx roland

Roland,
Not locking the back brakes is not a huge problem. Not locking the front brakes and a heavy pedal is a problem. There is an adjustment between the master cylinder and the power assist vacuum booster. That would be my first look. But lets ask a few more questions.

Is it a new vacuum assist cylinder/master cylinder assembly?
Where did you get it?
Rebuilt old proportioning valve? By who.
No pulling to either side?
Did you replace all the steel lines? Or are they your originals?

After these questions we may look at the routing of the lines. Could the proportuning valve be backwards. If that even occurred, you would have little front braking, but the back brakes should lock up like a big dog!!

Let’s dig further. I am out the rest of the day but will be back Sunday afternoon.

Rob

brakes

thanx for repling robert, i replaced the master cylinder with a rebuild from napa, the vacumm assist was new with the car when purchased, the prop valve was rebuilt from a brake and service shop parts business, on the prop valve, it has a i do not know the name of it it looks like a in line block, could i have the wrong prop valve for the car? i also used organic linings as i was told the semi metallic do not grab as good?

Did you replace the wheel cylinders? Since you bled the brakes, I'm assuming you are getting fluid to the rear. With the car in the air and brakes applied, can you still turn the tire by hand? Do you have the auto adjusters on correctly and the shoes adjusted? Just some ideas to look at.

Steve