ok 90% of the time my brakes are kinda soft but they do work and they do so well. my problem comes from i have been having a problem lately where ill be driveing along and i will hear a pop and for the next couple of stops or so i can barely touch the brakes and i feel like im gonna go through the windsheild. its in the rear brakes cause i have totaly redone the fronts and i hear the noise from the rear of the car.

I thought i might have something loose/out of adjustment nope its all as it should be and i checked the diff when i changed the fluid no problems there. the shoes are worn but not to need replacement and i had the drums checked and there supposed to be good. The only thing i can figure is that there is a lip in the inside of the drum and mabe its moving enough for the shoes to pop up onto that lip and that is what is causing the way it acts? im at a loss as to what could possibly cause this