1. Wheel cylinder
2. Protective cap
3. Piston
4. Piston collar
5. Cylinder body
6. Spring
7. Return spring
8. Regulator
9. Brake shoe
10. Regulator lever
11. Regulator spring
12. Pad retainer
13. Clamping spring
14. Hand brake lever
15. Washer
16. Retaining ring
17. Shoe rack
18. Plug
Removing
WARNING: Make sure the parking brake lever is fully released.
1. Remove the brake drum. If the drum is difficult to remove, proceed as follows. Remove the plug, then shorten the adjuster so that there is a gap between the shoes and the drum.
Insert two bolts into the holes in the drum and tighten until the drum separates.
2. After removing the brake shoe retainers, disengage the return spring by turning the shoes.
Be careful not to damage the wheel cylinder protective caps and the parking brake cable.
3. Remove the regulator.
4. Disconnect the parking brake cable from the lever of the manual drive of the pads.
5. Disconnect the manual shoe drive lever from the brake shoe by removing the circlip with a suitable tool (e.g. with a screwdriver).
Wheel cylinder check
By visual inspection, check that there are no brake fluid leaks through the sewn-in caps. After disassembling the cylinder, check the weight of the internal parts. They should be free of corrosion, signs of wear and damage.
When assembling the cylinder, be careful not to scratch the cylinder walls when installing the pistons.
Checking the brake drum
The working surface of the drum should be treated with sandpaper with a grit of 120-150.
If there are deep grooves on the working surface of the drum, stepped wear and other defects, bore the drum on the machine.
- Maximum inner diameter - 181 mm
- Maximum ovality - 0.03 mm
Checking the brake pads
Check the thickness of the brake pads (A).
- Nominal lining thickness - 4.0 mm
- Maximum allowable - 1.5 mm
Assembly and installation
1. Attach the lever of a manual drive of blocks and fix it with a lock ring.
2. Apply brake grease to the areas shown in the illustration.
3. Shorten the regulator as much as possible. Please note that the regulators have different threads: for the left wheel - left, for the right - right. An annular groove is extruded on the left wheel adjuster.
4. Attach the parking brake cable to the lever for the manual drive of the shoes.
5. Install all other parts.
Pay attention to the installation direction of the regulator.
7. Install the brake drum.
8. When installing a new wheel cylinder or repairing an old one, bleed the air from the hydraulic drive (see relevant section of this chapter).
9. Adjust parking brake (see section «Parking brake actuator, Adjustment»).