Just finish up my RD350 powered Gokart. We need to weld a bracket on . So i turned it up on it's side welded tab on . Looked ready to go, got a push start. Jump on the gas get down near the end of the block put the breaks on. Oh my they right to the floor. I Fly out on to Pacific Coast Hwy at rush hour. Manage not get hit by rush hour traffic . Yes I saw a car bumper miss me It was close. I guess when we tipped it air went in to break system from top master cylinder .