The drum brake hardware at a wheel consists of a drum, two brake shoes, return springs, hold-down springs, a wheel cylinder, and other miscellaneous hardware.
Brake Drum. The brake drum connects to the wheel hub. If a newer vehicle has drum brakes, they are on the back wheels. Similar to rotors, it may be possible to resurface the drums if they are thick enough. The drums should be machined equally as a pair.
Brake Shoes. Inside the drum is a set of brake shoes. When force is applied to the brake pedal or the parking brake is engaged, the brake shoes are forced out against the brake drum creating friction to slow and stop the wheels.
Wheel Cylinder. A wheel cylinder converts the fluid pressure in the brake lines to the mechanical motion of the shoes against the drums.