Hello, and welcome to JA!!! there is really no way to back off the rear park shoes. there is a adjustment for the park shoe, but can only access after the rotor is removed!!! if the rotors is stuck, trying tapping on the rotor with a hammer!!! sometimes during removal of rear rotors, the park brake shoe's will get damaged. it is always a good idea to replace the rear park shoes, while working the rear brakes!!!
Rear Brake Rotor Replacement
Notice: Support the caliper with a piece of wire to prevent damage to the brake line.
Important: Do not disconnect the brake hose from the caliper.