I just replaced all parts on the front and rear brakes. Drums, shoes, cylinders and hardware. Rotors, calipers and shoes. The master cylinder never ran empty. I did the rear brakes on one weekend and had a soft pedal but it still worked. I did the front this week end and when I bleed the brakes I have a solid pedal until I start the engine - then I have no pedal. With the truck off the ground the brakes do stop the wheels but there is no pedal. I've bled the system at the master cylinder and brakes. When I remove the vacuum from the booster I have a solid pedal but when the vacuum is restored I loose the pedal. Any ideas as to what I might have missed.