ok im trying to get my 40 working and stoping, iv had problems with the front brakes before so i rebuilt them and put on a new master cylinder. but i still cant get the brakes to work much at all. i have bleed them many times, i cant find the problem. when i press on the brakes i can still spin the tires w/ my feet. also every time i press on the brakes i hear an air leak, im assuming its my brakes booster, but would that effect how tight my brakes work?