Pic. 15.41. Front disc brake: 1 - brake hose; 2 - sealing gasket; 3 - support; 4 - brake disc
Removing
1. Drain the brake fluid.
2. Turn out a hollow bolt and disconnect a brake hose from a support.
3. Remove the seals.
4. Turn out screws and remove a brake disk.
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
1. To measure the torque after installing the brake pads, first measure the rotational resistance of the wheel bearing with the brake pads removed.
- (1) Remove the drive shaft.
- (2) Install a special tool in the hub as shown in Figure 15.42 and tighten it to the required torque.
Pic. 15.42. Installing a special tool in the hub to measure the moment of resistance to rotation of the wheel bearing with the brake pads removed
- (3) Using a spring dynamometer, measure the moment of resistance to rotation of the wheel bearing (pic. 15.43).
Pic. 15.43. Using a spring dynamometer to measure the moment of resistance to rotation of a wheel bearing
2. After installing the caliper assembly on the steering knuckle, install the brake pad assembly.
Warning. Keep oils, greases or other contaminants away from the running surfaces of the brake pads and brake disc.
3. If new brake pads will be installed, press the piston into the caliper cylinder (pic. 15.44). This can be done with a special tool or a hammer handle. At the same time, make sure that the piston is not warped and the surfaces of the piston and anther are not damaged. When the piston is depressed, the brake fluid is forced out of the brake cylinder into the reservoir. Therefore, constantly monitor the fluid level in the tank and, if necessary, pump out.
Pic. 15.44. Using a special tool to press the piston into the caliper cylinder
4. Be careful not to damage the piston boot when lowering the caliper into place, then install the guide pin.
5. After installing new brake pads, measure the torque resistance:
- (1) Start the engine and press the brake pedal 2-3 times.
- (2) Turn off the engine.
- (3) Rotate the brake disc 10 turns in the forward direction.
6. Using a spring dynamometer, measure the moment of resistance to rotation of the hub bearing (pic. 15.45).
Pic. 15.45. Using a spring dynamometer to measure the moment of resistance to rotation of a wheel bearing
7. Calculate the torque resistance of the new brake pads as the difference between the torque of the hub with brake pads and without brake pads.
Disk brake torque: max. 40 N
8. If the calculated torque difference exceeds the nominal value, replace the disc brake.
- Refill with brake fluid.
- Remove air from the hydraulic drive of the brake system.