Under the influence of brake fluid pressure, the pistons of the working brake cylinder move out of the cylinder and press
brake pads to the working surface of the brake drum. After releasing the brake pedal, under the influence of the coupling springs, the brake shoes sink the pistons into the cylinder and move away from the brake drum. In the working brake cylinder, a device for automatically adjusting the gap between the brake shoes and the brake drum is installed, which limits the sinking of the pistons into the cylinder. This maintains the optimum clearance between the brake pads and the brake drum
The rear brakes are also part of the parking brake system.
Device, scheme of the rear brake mechanism: 1 - lower coupling spring of the shoes; 2 - front brake shoe; 3 - clamping spring of the front shoe; 4 - spacer bar; 5 - upper coupling spring; 6 - working brake cylinder; 7 - shield of the brake mechanism; 8 - axial pin of the spacer lever; 9 - spacer lever; 10 - rear brake shoe; 11 - tip of the parking brake cable