1955 Chevy Truck. Heres what I have done so far. Installed a power booster and master cylinder , front disc brakes and 10 bolt chevy rear with drum set up . Installed residual valves and proportioning valve. Bench bleed the master cylinder and installed and have bleed the brakes a half dozen times. I still can't seem to get a good pedal. If I pump the brakes once the truck stops ok . But other than that the pedal pretty much goes to the floor with little stopping power. Any ideas ? Thanks