Rear wheel brake mechanism
1 – wheel cylinder; 2 – upper brake shoe tension spring; 3 – brake shoe lining; 4 – brake shield; 5 – inner plate; 6 – rear cable sheath; 7 – lower brake shoe tension spring; 8 – front brake shoe; 9 – Brake pad support plate; 10 – rivets; 11 – oil deflector; 12 – brake shoe guide plate; 13 – rear parking brake cable; 14 – rear cable spring; 15 – rear cable tip; 16 – rear brake shoe; 17 – support stand of the shoe; 18 – manual brake pad drive lever; 19 – rubber cushions; 20 – brake shoe spacer bar; 21 – finger of the manual brake pad drive lever
Wheel cylinder
1 – brake shoe stop; 2 – protective cap; 3 – cylinder body; 4 – piston; 5 – seal; 6 – support cup; 7 – spring; 8 – crackers; 9 – thrust ring; 10 – stop screw; 11 – nipple; A - slot on the thrust ring
(The original is on the portal VazBook)
Wheel cylinder parts
1 – piston assembly; 2 – cylinder body; 3 – stop screw; 4 – thrust ring; 5 – crackers; 6 – spring; 7 – support cup; 8 – seal; 9 – piston; 10 – protective cap
Rear wheel brake mechanism is drum type with self-adjusting shoes. Brake shoes 8 (see fig. Rear wheel brake mechanism) with linings, wheel cylinder 1 and other parts are mounted on brake shield 4, which is attached to the flange of the rear axle beam.
The clearance between the pads and the drum is adjusted automatically using a device located in the wheel cylinder 1. Its main element is a split thrust ring 9 (see fig. Wheel cylinder and fig. Wheel cylinder parts), mounted on piston 4 (1) between the flange of thrust screw 10 (3) and two crackers 8 (5) with a gap of 1.25–1.65 mm. The thrust rings are installed in the cylinder with an interference fit that ensures a shear force of the rings along the cylinder surface of at least 35 kgf, which exceeds the force on the piston from the tension springs of the brake shoes.
With the optimum clearance between the shoes and the drum, when braking, the shoes move apart until a clearance of 1.25–1.65 mm is selected between the screw flange and the thrust ring flange. This clearance ensures the movement of the shoes to create maximum braking torque.
When the linings wear out, the gap of 1.25–1.65 mm is completely eliminated, the flange on the stop screw 10 is pressed against the flange of the ring 9, as a result of which the stop ring shifts after the piston by the amount of wear. When braking stops, the pistons shift under the force of the tension springs until the crackers stop against the flanges of the stop rings. This maintains an optimal gap in the brake mechanism.