53 you shouldnt have to use one. most brake pedals don't come with a spring because it shouldn't need one to help pull the pedal back. if you bench bleed you master cylinder you know how hard the piston was to push in and that should be enough to push the pedal back up. if it want push it back up, then it sounds like your pedal might be to tight or the rod is adj. out to far or something. wouldn't hurt to check on that. most of the time the extra spring is for anti rattle or to take the play out of the pedal. but if i had to put a spring on mine to get my brakes right id find out why. the spring in the master cylinder should push it back.