This is a typical front drum brake. Brake fluid under pressure inside the brake cylinder pushes the brake shoes outward into the spinning drum. When the brake pedal is released, return springs pull the shoes away from the drum. This is a self-adjusting drum brake. The self-adjustment lever is controlled whenever we back up and apply the brakes. Releasing the brake pedal allows the self-adjuster spring to pull the lever down, which turns the star-wheel adjuster, moving the shoes closer to the drum.