On some Subarus, Hondas and other vehicles utilizing a “drum-in-hat” type parking brake system operated in a corrosive environment (road deicers, salt, etc) the new rear brake rotor may rub against the backing plate. This condition may be caused by corrosion between the backing plate and knuckle assembly that has “jacked” the backing plate away from the knuckle such that it makes contact with the brake rotor. While some may machine/grind the inboard-most edge of the parking brake drum, the correct course of action is to disassemble the parking brake, remove the backing plate from the knuckle, thoroughly clean all components (replace parts as necessary) and reassemble.

Courtesy of Centric Parts