Allen, I take it you have the outboard braked rear. The PBR brakes have a "parking lever adjuster screw" on the back of the caliper that you would never find unless you knew it was there. But before you even think of screwing around with it, check and make sure that your parking brake lever on the caliper is releasing fully and not dragging. Here's a pic, do you see how the cable pulls the lever? It should release fully and not be tight when the brake is off.
