Removing
To remove the front disc brake, perform the following steps in sequence.
1. Drain the brake fluid.
Pic. 14.20. Front disc brakes: 1 - hollow bolt (15 Nm); 2 - sealing ring; 3 - brake hose; 4 - bolt (100 Nm); 5 - brake disc; 6 - support
2. Turn away a special bolt and disconnect a brake hose 3 (pic. 14.20) from the support.
3. Remove O-rings 2.
4. Using the special tool, remove the brake disc 5 assembly.
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
1. To measure the rotational resistance force after installing the brake pads, first measure the rotational resistance of the wheel bearing with the brake pads removed.
2. Remove the drive shaft.
Pic. 14.21. Installing a special device in the hub to measure the resistance to rotation of the wheel bearing with the brake pads removed: 1 - bolt; 2 - nut (180 Nm); 3 - special tool МВ990998
3. Install the special tool in the hub as shown in fig. 14.21, and tighten it to the required torque.
Pic. 14.22. Using a spring dynamometer to measure the resistance to rotation of a hub bearing
4. To measure the resistance to rotation of the hub bearing, use a spring dynamometer (pic. 14.22).
5. After installing the caliper assembly on the steering knuckle, install the brake pad assembly.
Attention! Keep oils, greases or other contaminants away from the running surfaces of brake discs and brake pads.
Pic. 14.23. Using the special tool MB990520 (1) for installing a piston in a wheel brake cylinder
6. Clean the piston and insert it into the wheel brake cylinder (pic. 14.23).
7. Be careful not to damage the piston boot when lowering the caliper assembly into place, then install the roll pin.
8. Measure the rotational resistance after installing new brake pads as follows:
- start the engine and press the brake pedal 2-3 times;
- stop the engine;
- make 10 revolutions of the brake disc forward.
9. Using a spring dynamometer, measure the moment of resistance to rotation of the wheel bearing in forward rotation (see fig. 14.22).
10. 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, which should not exceed 40 Nm.
11. If the resulting torque difference is greater than the nominal value, replace the disc brake assembly.
12. Fill in a brake liquid.
13. Remove air from the hydraulic drive of the brake system.