Attention! Do not use compressed air or petrol-based solvents when working on the brake system.
Disc brakes have built-in brake lining wear indicators on the pads. Information about the wear of the brake pad is displayed on the instrument panel and its indication requires immediate replacement of the brake pads.
Lining thickness
The thickness of the outer brake pads can be determined without removing the wheel. In this case, it is necessary to set the car so that a socket for the wear indicator appears in the opening of the disk (pic. 2.31).
![](https://www.bmwman.ru/img/x5/0134.jpg)
Install fixture «34.1.260» through the rim into the socket, press the tool against the brake lining. Move the ring (1) as far as it will go in the direction indicated by the arrow and read the readings.
A friction lining 5 mm thick ensures a driving range of at least 3,000 km. Its minimum allowable thickness is 3.0 mm. If its thickness approaches the limit value, then it is necessary to remove the block and check the actual degree of its wear by the caliber and evaluate the further possibility of its operation. Experience shows that the brake lining is reduced by 1 mm when the car runs 1000 km in unfavorable conditions. If the pad thickness is less than 3.0 mm or it is worn unevenly, replace the brake pads (4 things.) throughout the bridge.
Attention! If the slightest signs of a malfunction are found in the brake system, movement is strictly prohibited until the cause of its occurrence is eliminated.
Brake lines and hoses
Brake fluid circulates through rigid plastic-coated steel tubes and flexible reinforced hoses at the front wheels and as connections at the rear axle. Constant and thorough inspection of all lines is very important for traffic safety.
Drum parking brake
To inspect the parking brake drum mechanism, the rear brake disc must be removed as described in section «Brake system». Inspection of the drum mechanism is carried out in the following order. Inspect the rear brakes for leaks of brake fluid or grease contamination. Measure the thickness of the friction linings on the rear brake shoes (pic. 2.32).
![](https://www.bmwman.ru/img/x5/0135.jpg)
If at least one lining is 2.0 mm or less thick above the rivet heads or metal base at its thinnest point, replace all shoes (4 things.).
Parking brake lever
Check the reliability and travel of the parking brake lever in the following order. Place the car on an inclined plane. While holding it on the service brakes, apply the parking brake, while the gearbox should be in neutral, release the service brakes. If the vehicle rolls, the parking brake must be adjusted, see section «Brake system».
- Park the vehicle on a level surface, raise the rear of the vehicle and place it on jackstands.
- Tighten the parking brake 1 notch. Turn the wheels by hand, no braking should be tested.
- Tighten the parking brake 2 teeth. The parking brake indicator on the control panel should come on. Turn the wheels by hand, braking should appear.
- Tighten the parking brake 3 teeth. It is not possible to turn the wheels by hand, the wheel must experience full braking.
- It is allowed to deviate the difference of the circumferential force on the left and right wheels by no more than 30% of the large value (measured on a roller test bench). If the circumferential force difference is higher, re-adjust.
- Check the spreader lever for ease of movement and lubricate if necessary.
- If the parking brake lever travel exceeds more than 10 teeth of the adjusting screw (ratchet), it must be re-adjusted.