I have a 1993 conversion van and the rear brakes do not realease after stepping the on brakes. I have disconnected the e-brake, replaced master cylinder, replaced both wheel cylinders ,brake line in rear and brake shoes.Does anyone have any ideas I am very confused , and scracthing my head. Thanks

 

By any chance, is the backing plate worn where the shoes ride on the plate? If there are grooves in the backing plate, it can hold the shoes out. Also check to see if the return springs are strong enough to pull the shoes back in.

 

I'd try to isolate the problem. Mechanical or hydraulic, when the brakes are locked on open a bleeder on one of the wheel rear cylinders. If you have pressure its a hydraulic issue if not most likely mechanical.