Chevrolet Repair: 96 Silverado brakes, brake light switch, master cyl

Question
We recently had a brake line rupture.  We have replaced the brake line, power booster, master cylinder and brake pedal switch.  After bleeding all brakes we have a good pedal when the truck is not running-- but after truck is started brake pedal goes all the way to the floor and truck will not shift out of park.  What do we look at next?

Answer
HI MARTHA,THE BRAKE PEDAL IS HARD WHEN NOT RUNNING BECAUSE THE TRUCK DOES NOT HAVE ANY VACUUM IN THE BOOSTER MAKING POWER ASSIST..THIS IS NORMAL. IF YOU PRESS REAL HARD WHEN THE TRUCK IS NOT RUNNING THE BRAKE PEDAL WILL GO TO THE FLOOR. THE TRUCK WILL NOT SHIFT OUT OF PARK BECAUSE WHEN YOU REPLACED THE MASTER CYLINDER AND BOOSTER YOU DID NOT HOOK UP THE BRAKE LIGHT SWITCH CORRECT WHICH SENDS POWER TO THE SHIFTER INTERLOCK. [PREVENTS GOING IN TO GEAR WITHOUT OUT YOUR FOOT ON THE BRAKE PEDAL.] SAFTY DESIGN..CK THE BRAKE LIGHT SWITCH DOWN ON AT THE BRAKE PEDAL.I THINK YOU WILL FIND SOMETHING NOT HOOKED UP CORRECT.IF ALL IS HOOKED UP CORRECT CK ALL THE FUSES.YOU MIGHT OF POPPED A FUSE WHEN REPLACING THE MASTER CYL OR BOOSTER...AS FAR AS YOU NOT HAVING A BRAKE PEDAL.YOU STILL HAVE TRAPPED AIR IN THE SYSTEM..WILL NEED TO BLEED AGAIN. THIS HAS ANTI LOCK BRAKES SO THERE MAYBE ALOT OF AIR TRPAED IN THE ABS UNIT. JUST BLEED AGAIN.DID YOU BENCH BLEED THE MASTER CYLINDER FIRST BEFORE PUTTING IT ON THE TRUCK.IF NOT,, REMOVE IT AND BENCH BLEED IT FIRST..THESE WILL TRAP AIR AND WILL HAVE A HARD TIME REMOVING IT ONCE ON THE TRUCK..[BEEN THERE MANY TIMES] AFTER THAT START WITH THE RR,LF,LR AND FINISH WITH THE RF..I WILL ASSUME YOU KNOW HOW TO BLEED THE SYSTEM...IF NOT GET BACK TO ME.. I HOPE THIS HELPS YOU,,,TOM...