Fig. 8.6. Brake mechanism of back wheels: 1 — a bolt of fastening of the wheel cylinder; 2 — the wheel cylinder; 3 — the pumping valve; 4 — a brake board; 5 — a block; 6 — a protective cover; 7 — the piston; 8 — a persistent ring; 9, 10, 14 and 28 — springs; 11 — a razzhimny link; 12 — the driving lever of the parking brake; 13 — a plate of fastening of blocks; 15 — the forelock; 16 — a nut; 17 and 18 — washers; 19 — a bolt; 20 and 22 — caps; 21 and 23 — the clown's plugs; 24 — the clown; 25 — the clown's axis; 26 — a nut; 27 — cups; 29 — a core; 30 — a cable of the parking brake system

Brake mechanisms of back wheels kolodochny, drum type (fig. 8.6). The brake mechanism consists of a board of a brake 4 on which fasten the working cylinder 2, a support of blocks with a plate 13, blocks 5.

Blocks the top ends enter cuts of cores of pistons, and lower concern a basic plate on which keep by means of coupling springs 9 and 14. Side fixing of each block on a board is provided in three points of fastening to which it is drawn in by a spring 28.

Wheel cylinders have the special device supporting a constant gap between the brake drum and blocks in process of wear of slips. This device consists of the persistent cutting metal ring 8 installed with a tightness in the brake cylinder. The section of a ring settles down in the top part of the cylinder at an opening for pumping. The piston 7 is inserted into the central opening of a persistent ring so that after its turn on 90 ° the cut on a core of the piston was parallel to the plane of fastening of the cylinder to a board. The piston rests against a ring and can freely move in it towards blocks within 1,7 — 1,9 mm.

In process of wear of brake slips and a drum the piston when braking under pressure of liquid moves in the cylinder, entraining a persistent ring 8. After braking the piston under the influence of coupling springs of blocks will move concerning a ring to the size stated above, than will provide a constant gap between blocks and a drum.

Brake drums — tselnolity, from gray cast iron. Details of the parking brake system enter the back brake mechanism: driving lever 12, razzhimny link 11 and details of mechanical adjustment 21, 23, 24, 25.