BMW 3 Series E30
since 1983-1994 release
Repair and operation of the car
+ 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
10.3. 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 brakes
10.8. Main cylinder of brakes
10.9. Vacuum amplifier of brakes
10:10. Cable(s) of the emergency brake
10:11. Adjustment of the emergency brake
10:12. Mechanism of the emergency brake
10:13. Brake pedal
10:14. Braking signal switch
10:15. Hoses and lines of a hydraulic actuator of brakes
10:16. Removal of air from a hydraulic actuator of brakes
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
+ 14. Useful tips
The scheme of double-circuit brakes (the option with disk lobbies and back brakes is shown) and the drive of the emergency brake
Device of a forward brake
All cars are completed with forward disk brakes and also back disk or drum brakes. On all cars forward and back brakes are self-regulating. On some cars of late release the anti-blocking brake system (ABS system) is installed.
The hydraulic system consists of two separate contours. For each of contours the separate section is provided in the main brake cylinder. If in one of contours there is a leak or other malfunction, then other contour remains to workers.
The vacuum amplifier of brakes uses vacuum in a collector of the engine and atmospheric pressure to provide increase in effort of braking, it is established on a partition in a motor compartment
The emergency brake has the drive on back wheels by means of the cable and the lever located in the central section of salon. The emergency brake is a part of a back drum brake, the gap between blocks and drums is regulated automatically. On cars with back disk brakes the lever of the emergency brake puts two blocks located in the central part of a brake disk in action. 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 they need to be replaced, then the red precautionary lamp on the dashboard lights up. If blocks are not replaced, then it can lead to damage of a disk.
On some cars the additional control lamp of wear of blocks which lights up only at the pressed brake pedal 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 insulating covering of the sensor. When replacing blocks always check the sensor(s). When replacing blocks after fire of an alarm lamp, it is necessary to replace as well the sensor(s).
Upon completion of any works with units of the brake system always check efficiency of braking of the car. Check of brakes should be carried out on the flat, pure, dry road with low-heavy traffic.
Check of brakes should be carried out at various speeds, by weak and sharp pressing a brake pedal. The car has to stop without having changed the direction of the movement. Do not allow the movement by a skid since it leads to reduction of efficiency of braking and decrease in stability of the car.
Efficiency of braking is also influenced by a condition of tires and the angles of installation of wheels.