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
   10.2. 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 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


10.9. Vacuum amplifier of brakes


Returnable spring of a pedal of a brake(s), lock ring of an axis of a pedal (b) and axis (c)

On an insert the removed axis of a pedal and a bracket of fastening of an axis is shown.

Drive of the vacuum amplifier

1. Dustproof cover

2. Holder

3. Screen

4. Air filter


1. On the idle engine press a brake pedal until the course of a pedal does not cease to change.
2. Press and hold a pedal, then start the engine. If the pedal slightly goes down, then the cylinder is serviceable.

Tightness check

1. Start the engine and 1–2 min. later stop. Slowly press a pedal several times. If the first course of a pedal gradually decreases after the second or third time, then the vacuum amplifier is tight.
2. Press a brake pedal on the working engine and, holding a pedal, stop the engine. If during 30 sec. pedal does not move, then the vacuum amplifier is tight.

The faulty amplifier of brakes is subject to replacement.

Removal and installation

1. Remove the main brake cylinder.
2. Disconnect a vacuum hose from the amplifier.
3. From salon remove a box for trifles and the lower left facing panels on the left side.
4. Remove a bracket of fastening of an axis and remove a fork axis, disconnect a pusher from the lever (on cars with the right wheel) of or from a pedal (on other cars). On cars with the left wheel also disconnect a returnable spring of a pedal of a brake.
5. Turn off four nuts of fastening (arrow) and get the vacuum amplifier from a motor compartment.
6. Check a condition of the porous filter. If it is polluted, then wash out it in weak soap solution. If it is not possible to wash out, then replace the filter.
7. Installation is carried out upside-down. Tighten nuts of fastening of the amplifier with the set moment. Before dressing a cover on the filter be convinced that dredging in the filter is displaced concerning dredging on a damper on 180 °.
8. Adjust distance And (distance from the center of an axis of a fork on a brake pedal to a partition/wall of a motor compartment). Tighten a lock-nut, then adjust height and a free wheeling of a pedal of a brake, and also the braking signal switch. Tighten nuts of fastening of the amplifier with m 22–24 N.' moment.


On the car with the right wheel the pedal of a brake is on the right side of salon, it is connected to the left side in bulk. Adjustment of draft is carried out on the left side, however the distance is measured on the pedal.

9. Install the main cylinder and attach a vacuum hose.
10. Check work of brakes.