Need Brake help Please

[tincan1966]

You said you didn't have any brake lines installed by the shop? Were your front lines already split? I see you have a proportioning valve installed and what appears to be new lines attached to it.

My initial guess would be that maybe the rear brakes need adjusted up a little tighter. This could cause the MC to actually bottom out.

There's also several other things, depending on the installation.
Did the installer redrill the brake pedal and move the linkage down 1" from the original pushrod hole?
Is the pushrod adjusted so that it is against the stop at the top of the travel without the brakes applied?

When we install power brakes on theses trucks, we do move the pushrod down 1", also we make sure the rubber stop is in place for the pedal to return against, then we adjust the pushrod so there is about 3/4" free travel measured at the pedal. With the brakes properly adjusted and bled, your pedal travel should only be roughly 1/2 the distance to the floor, and that's with leaning on them pretty hard.