Self energizing brake shoes do NOT work well in Reverse...If the car wants to stop going backwards, I'd bet Some idiot installed the shoes backwards. (Short shoe in the rear instead of the front)..You wouldn't believe how many people think they can install their own brake shoes and get either BOTH long shoes on ONE SIDE, or long shoe in the front, and short in the rear. Then, they want to go off when it won't pass State inspection...