ON MY 1996 CHEVY 1500, I HAVE PROBLEMS WITH THE BRAKES. I JUST REPLACED THE REAR WHEEL CYLINDERS, AND THE MASTER CYLINDER, 3 WEEKS AGO. NOW NO BRAKES GOES TO THE FLOOR, HEAR AIR WHEN PRESSING NRAKES, AND THE MASTER CYLINDER IN BONE DRY. NO FLUID ON REAR WHEELS, I CHECKED THEM, COULD IT BE THE POWER BRAKE BOOSTER.