Took the truck in the sig in to replace/check the front brakes. They found the calipers were dragging on the front rotors and had eaten them up. Rotors and calipers replaced. Put it back together and brakes are strong without power assist, but when you fire up the truck the pedal goes to the floor. When I stopped by this morning they were bleeding the brakes, but there was no air in the system. I think these guys are lost. Any ideas?

 

they are not waiting for the booster to clear when mechanically bleeding the lines. they are sucking in the air bubble back and forth. the bubble goes back to vent at the booster, hence the pedal sinking but applied when engine running.

sorry i can't explain it better. loved my 96 half ton.......hubby pried it out of my hands to sell. enjoy yours.

 

Any updates on this 96WhiteBuffalo? I replaced the front calipers and brake lines on my 97 and I'm having the same symptoms as you describe. Pedal is rock hard after bleeding, but when I fire the truck up and hit the brakes, the pedal sinks to the floor and won't come back up. The truck has no brakes at all at this point. Just wondering if you got it figured out.

MIke