9.10.4. Replacement of blocks of brake mechanisms of back wheels

At operation of the car it is necessary to check periodically a condition of brake drums, brake shoes, coupling springs, the protective covers influencing operability of brake mechanisms. In process of wear of brake slips the gap between them and drums is supported automatically and does not need additional adjustment.

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




Degree of wear of brake slips should be controlled through viewing openings in a brake board 4 (see fig. 8.6), previously having removed caps 22. Blocks should be replaced new if thickness of a slip decreased to 1 mm in a zone of an observation port.
Blocks should be replaced in the following order:
- to remove wheels;
- to clear brake mechanisms of dirt and to be convinced of free rotation of the brake drum;
- to turn out three screws and to remove a drum from a nave. If the drum sits hardly, then to screw three bolts of M10 in carving openings and, serially rotating them, to remove a drum. At removal of drums it must be kept in mind that they are processed assembled with a nave and therefore inadmissibly to interchange the position of them. In order that the reel could be installed on a nave only in one situation, openings of its fastening are located to a nave unevenly. It is necessary to remember that if to remove from the car at least one drum, then it is not necessary to press a brake pedal as at the same time pistons will go out of wheel cylinders and brake fluid will flow out from system;
- to remove the top and lower coupling springs of blocks, springs of side fixing of blocks;
- to remove worn-out blocks with details of the parking brake;
- to shift persistent rings and pistons in the cylinder at an identical size from cylinder end faces before contact of pistons. For this purpose it is necessary to put an aluminum or copper mandrel to a core of the piston and to move with easy blows of the hammer hornets;
- to collect new blocks with details of the parking brake, having adjusted a razzhimny link at the minimum length;
- to establish new blocks, coupling springs and springs of side fixing of blocks. Blocks the top ends have to enter cuts of cores;
- to install brake drums, previously having greased a landing corbel with graphitic lubricant or Litol-24.

Prevention
The vystupaniye of heads of screws for the drum flange plane is not allowed.

- to press a brake pedal by effort 150 — 200 N (15 — 20 kgfs) at the working engine to choose gaps in automatic adjustment. To release a pedal.