BMW 3 series E30

Since 1983-1994 of release

Repair and car operation

+ 1. The maintenance instruction
+ 2. Maintenance service
+ 3. The engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. An exhaust system
+ 8. Transmissions
+ 9. Coupling
- 10. Brake system
   10.2. Specifications
   10.3. Antiblocking system (ABS)
   10.4. Колодки disk brakes
   10.5. A support of a disk brake
   10.6. A brake disk
   10.7. Колодки drum-type brakes
   10.8. The main cylinder of brakes
   10.9. The vacuum amplifier of brakes
   10.10. A cable () a manual brake
   10.11. Adjustment of a manual brake
   10.12. The mechanism of a manual brake
   10.13. A brake pedal
   10.14. The switch of a signal of braking
   10.15. Hoses and lines of a hydrodrive of brakes
   10.16. Removal of air from a hydrodrive of brakes
+ 11. A running gear
+ 12. A body
+ 13. An electric equipment
+ 14. A good advice

10.8. The main cylinder of brakes

The prevention

It is recommended to replace the removed cylinder new or restored as in a case подтекания replacement of details of the old cylinder with new details from ремкомплекта positive result does not give a liquid. As a rule, the old cylinder will be worn strongly out, of what it will be possible to be convinced, having spent considerable time for its dismantling.

The main cylinder and the vacuum amplifier of brakes

1. A nutritious tank
2. A stopper of a tank with the switch of a control lamp of level
3, 6. A vacuum hose
4. A collar
5. The return valve (on models 325i)
7. A collar
8. The return valve (on all models except 325i)
9. Скоба
10. A pusher plug
11. An axis
12. A nut
13. A cover
14. A washer
15. Гаситель pulsations
16. A pusher
17. The filter
18. A sealing ring
19. A restrictive bolt
20. The main cylinder
21. Nuts of fastening of the main cylinder
22. Уплотнители a tank
23. A collar
24. The vacuum amplifier of brakes
25. A knee


The main cylinder with the attached vacuum amplifier take places in the left part of a motor compartment.

1. To remove the main cylinder, disconnect a conducting socket (the marksman from above), disconnect hydrodrive tubes (the bottom right arrow) and turn away two bolts of fastening (the bottom left arrow).
2. Remove as much as possible a brake liquid from a tank.
3. Turn on the union of tubes of a hydrodrive on the main cylinder, immediately muffle tubes and apertures. Take tubes aside.
4. Disconnect from the main cylinder sockets, turn away a nut of fastening of the cylinder to the vacuum amplifier and remove the cylinder. Remove and replace a sealing ring (1).

Removal of air from the main cylinder

1. Before installation of the new or restored cylinder it is necessary for pumping over on the special machine tool. For this purpose fix the cylinder in a vice through a soft lining (otherwise the cylinder can burst!).
2. Establish заглушки with a carving in apertures of unions of tubes of a hydrodrive and slightly tighten them that through them did not take place air.
3. Fill a tank with a brake liquid of recommended type.
4. Remove one of заглушек and enter the piston into the cylinder, having pushed its screw-driver to remove air.
5. Without releasing the piston, tighten заглушку.
6. Repeat procedure until then while the brake liquid will not start to follow from an aperture under the union without air bubbles. Constantly add a brake liquid in a tank of the main cylinder.
7. To accelerate procedure of preliminary prorolling of the cylinder it is possible to muffle an aperture under the union a finger, however upon termination of procedure tighten заглушку and repeat procedure on other aperture.


1. Establish the main cylinder (together with a new sealing ring) and wrap by hand fastening nuts.
2. Turn the union of tubes of a hydrodrive, without applying considerable efforts.
3. Tighten all the union and a nut of fastening with the set moment.
4. Fill the main cylinder with a liquid, then pump over it (if preliminary prorolling was not carried out), pump over all hydrodrive.
5. At cylinder prorolling on the car ask the assistant to press some times a pedal and to keep it in the pressed position. Release the union to allow to leave to air and a liquid, then tighten. Repeat procedure for both unions until then while in a brake liquid air vials will not disappear. Check up work of brakes before car operation.