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Pic. 27. Wheel brakes: 1. Brake pads; 2. Compression spring pads; 3. Bolts for fastening the cylinder to the guide pins; 4. Bolts connecting the cylinder to the caliper; 5. Cylinder; 6 piston; 7. O-ring; 8. Guide pin; 9. Protective finger cover; 10. Shoe pad, 11. Shoe guide; 12. Protective cover; 13. Disc brake; 14. Caliper; 15. Front wheel hub; 16. Brake cylinder hose; 17. Guide pins; 18. Piston protective cover; 19. Bolts of fastening of the brake mechanism to a rotary fist; 20. Fitting for pumping the brake drive; 21. Block of the brake mechanism; 22. Shoe guide spring; 23. Expanding bar; 24. Top coupling spring pads; 25. Protective cap of the wheel cylinder; 26 Stop screw, 27. Brake bleeder; 28 Brake shield; 29. Rusks; 30. Thrust ring; 31. Spring; 32. Fitting of the liquid supply pipe; 33. Support cup; 34. Sealant; 35. Wheel cylinder piston; 36. Shoe stop; 37. Finger of the lever of a manual drive of pads; 38. Lever for manual drive of brake pads; 39. Parking brake cable. 40. Rope spring; 41. Rope tip; 42. Lower coupling spring pads; 43. Base plate pads; 44. Shoe guide plate; 45. Rivets for fastening plates.
The brake mechanism of the front wheel is disk, consists of a shoe guide 11, a caliper 14, two brake shoes 1 and a brake disc 13. The shoe guide is made of high-strength cast iron in the form of a bracket, which has four bosses. In two of them, threaded holes are made for the bolts 19 for fastening the guide pads to the steering knuckle, in the other two, holes are drilled for the guide pins 8 of the caliper. The pad guide has a longitudinal groove through which the brake disc passes, and two openings for placing the brake pads. The configuration of the openings is made in the form of brake pads. In addition, in the side openings there are two shelves, to which 2 brake pads are pressed by springs. All this creates a tight fit of the brake pads in the guide and does not allow vibration of the pads. The caliper is cast from ductile iron. It has a groove for the brake pads on top, and in the center there is a through viewing window, in which the tides of the brake pads are placed. Through this window, the condition of the brake pads is visually determined. Springs 2 rest against the window steps, as a result of which they press the pads against the guide and fix the pads relative to the caliper. The caliper is attached with two bolts 4 to the flange of the wheel cylinder, forming "floating" bracket.
To ensure joint "swimming" caliper and wheel cylinder relative to the guide, they are connected to the guide pads not rigidly, but with the help of fingers 8, which are installed in the holes of the guide. The pins are bolted 3 to the flange of the wheel cylinder. During assembly, the pins are lubricated to prevent corrosion of the pins to provide a constant force to move the caliper regardless of how old the vehicle is. A protective cover 9 is put on the annular grooves of the finger and the guide, which protects the finger shaft from environmental influences.
Brake pads are steel, have a figured shape, which ensures their tight fit to the guide pads. At the top, the pads have a tide, which is located in the caliper window. Spring 2 is attached to the shoe with a finger. When installed, the caliper presses on the spring, ensuring that the shoes are pressed against the guide. A friction lining 10 is glued to the block. One of the blocks can have a wire for the indicator of lining wear.
The wheel cylinder is attached to the caliper and the shoe guide with bolts 3 and 4. A hollow piston 6 is installed in the cavity of the wheel cylinder 5, which is sealed in the cylinder with a rubber ring 7. This ring has a trapezoidal shape and is located in the cylinder groove. It tightly covers the surface of the piston. As the piston moves, it drags the ring along with it, twisting it in the cylinder groove. Due to the elasticity of the sealing ring, the piston returns to its original position when released. The cylinder cavity is protected by a rubber cover 18. Two holes are made in the cylinder, a fitting 20 is screwed into one for pumping the brake mechanism drive, and into the other, a hose fitting 16 for supplying fluid.
The brake disc 13 is cast iron, on the inside it is closed with a protective cover 12, which is attached to the steering knuckle.
The brake mechanism of a back wheel drum with automatic adjustment of a backlash between pads and a drum. It is mounted on a support plate 28, which is mounted on the rear suspension arm flange together with the rear wheel axle. In the lower part of the shield with two rivets 45, a package of plates is fastened, one of which is a support 43 for brake shoes 21. Other plates (44) direct the movement of the lower part of the shoes on the base plate, limiting their axial movement. A wheel cylinder is attached to the top of the shield with two bolts. The brake pads are pulled together by the upper 24 and lower 42 springs, which press the pads to the lower support and to the stops 36 of the pistons of the wheel cylinder. Additionally, the pads are held in the middle part by guide springs 22, which are connected at one end to the edge of the pad, and at the other end to the support shield pin. Due to the non-rigid connection of the pads with the brake shield, they self-adjust at the moment of braking.
The device for automatic adjustment of the gap between the pads and the drum is located in the wheel cylinder. Its main element is a split thrust ring 30 mounted on the piston 35 between the shoulder of the thrust screw 26 and two crackers 29 with a gap of 1.25-1.65 mm. Thrust rings are installed in the cylinder with an interference fit, providing a shear force of the ring along the cylinder mirror of at least 35 kgf, which exceeds the force on the piston from the coupling springs 24 and 42 of the pads. When the linings are worn, the gap of 1.25-1.65 mm is completely eliminated, the shoulder on the thrust screw 26 is pressed against the shoulder of the ring 30, as a result of which the thrust ring is shifted after the piston by the amount of wear. With the cessation of braking, the pistons are shifted by the force of the coupling springs until the crackers stop against the collar of the thrust ring.
On the rear pads, levers 38 of the manual drive of the pads are fastened with fingers 37.
The brake drum is cast from an aluminum alloy, its working surface is formed by a cast-iron insert cast inside the drum. The drum is attached to the flange of the rear wheel hub together with the wheel disk with four bolts.