On my '54 6100, my brakes were working fine on Tuesday. Wednesday morning I get in it and the pedal goes to the floor. I checked the master cylinder and there is just a little bit of fluid in it. I don't have any leaks (the truck sits on clean concrete so it would be easy to spot). I had White Post rebuild the hydrovac booster but my concern is since I don't seem to have a leak on any lines, master cylinder or wheel cylinders, I can only assume that I have blow back from the hydrovac going to the motor and is being burned up. Has anyone else had this issue and what would be my next step. I got the hydrovac booster back from White Post in January.