E30 series BMW 3

since 1983-1994 of release

Repair and car operation

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
- 10. Brake system
   10.2. Specifications
   10.3. Anti-blocking system (ABS)
   10.4. Blocks of disk brakes
   10.5. Support of a disk brake
   10.6. Brake disk
   10.7. Blocks of drum-type brakes
   10.8. Main cylinder of brakes
   10.9. Vacuum amplifier of brakes
   10.10. Cable (ы) hand brake
   10.11. Adjustment of the hand brake
   10.12. Mechanism of the hand brake
   10.13. Brake pedal
   10.14. Switch of a signal of braking
   10.15. Hoses and lines of a hydraulic actuator of brakes
   10.16. Air removal from a hydraulic actuator of brakes
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Good advice


10. Brake system

10.1. Introduction


The scheme of double-circuit brakes (the option with disk lobbies and back brakes is shown) and a drive of the hand brake

1. Cables of the hand brake
2. Support of a back brake
3. Disk of a back brake
4. Tube of the highway of a hydraulic actuator
5. Pedal
6. Main cylinder of brakes
7. Support of a forward brake
8. Disk of a forward brake
9. Nutritious tank of brakes and coupling hydraulic actuator
10. Vacuum amplifier
11. Lever of the hand brake

Device of a forward brake

1. Bolt
2. The union for air removal
3, 17. Support axis
4, 7. Cover
5. Piston
6. Cover
8. Sensor of wear of brake shoes
9. Block
10. Screw of fastening of a disk
11. Continuous disk
12. A ventilated disk
13, 14, 18. Bolt
15. Support arm
16. Cylinder sealant
19. Support

All cars are completed with forward disk brakes and also back disk or drum-type brakes. On all cars lobbies and back brakes are self-regulating. On some cars of late release the anti-blocking brake system (ABS system) is established.

Hydraulic system

The hydraulic system consists of two separate contours. For each of contours in the main brake cylinder the separate section is provided. If in one of contours there is a leak or other malfunction, other contour remains to workers.

Vacuum amplifier

The vacuum amplifier of brakes uses vacuum in a collector of the engine and atmospheric pressure for this purpose what to provide increase in effort of braking, it is established on a partition in a motor compartment

Hand brake

The hand brake has a drive on back wheels by means of a cable and the lever located in the central section of salon. The hand brake is a part of a back drum-type brake, the gap between blocks and drums is regulated automatically. On cars with back disk brakes the lever of the hand brake puts in action two blocks located in the central part of a brake disk. The gap between blocks and drums is regulated manually.

System of the prevention of wear of brake shoes

If blocks are worn-out to such an extent that it is necessary to replace them, the red precautionary lamp on the dashboard lights up. If blocks are not replaced, it can lead to disk damage.

On some cars the additional control lamp of wear of blocks which lights up only at the pressed pedal of a brake is established, warning, thus about fast replacement of blocks.

The sensor of wear is attached to brake shoes. The sensor settles down on the left forward wheel, on some models there is one more sensor on the right back wheel. The sensor of wear provides short circuit of contacts at wear of a block to some set limit. Fire of a lamp of wear of blocks means that the disk of a brake erases an insulating cover of the sensor. At replacement of blocks always check the sensor (and). At replacement of blocks after fire of an alarm lamp, it is necessary to replace as well the sensor (and).


On termination of any works with units of brake system always check efficiency of braking of the car. Check of brakes should be carried out on the equal, pure, dry road with low-heavy traffic.

Check of brakes should be carried out on various speeds, by weak and sharp pressing a brake pedal. The car should stop without having changed the movement direction. Do not allow movement yuzy since it leads to reduction of efficiency of braking and decrease in stability of the car.

Efficiency of braking is influenced also by a condition of tires and corners of installation of wheels.