You need to raise and support the vehicle, remove the tire and wheel assembly and the rear brake rotor, retract the park brake shoe adjuster to ease removal, remove the upper park brake shoe retainer spring, the park brake shoe adjuster, the rear park brake shoe hold down spring, the lower park brake shoe retainer spring and the rear park brake shoe, the front park brake shoe hold down spring and the front park brake shoe, and then clean the rear brake backing plate with denatured alcohol or equivalent and allow to dry.