wellllll-------
if your calipers aren't releasing it won't push back, buttttttt-----if your pedal isn't retracting the plunger , then your calipers won't have the pressure released---both ends of the master don't close/vent at the same time--that way pressure can be applied to one end of the car momentarily before the other--keeps the fronts released as a driver keeps litely touching the pedal---you know-the guy(or gal) thats in front of you that keeps tapping the pedal and blinking his stop lites in your face!!!!