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

10.8. Main cylinder of brakes



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

Main cylinder and vacuum amplifier of brakes

1. Nutritious tank
2. A tank stopper with the switch of a control lamp of level
3, 6. Vacuum hose
4. Collar
5. The return valve (on models 325i)
7. Collar
8. The return valve (on all models except 325i)
9. Bracket
10. Pusher fork
11. Axis
12. Nut
13. Cover
14. Washer
15. Quencher of pulsations
16. Pusher
17. Filter
18. Sealing ring
19. Restrictive bolt
20. Main cylinder
21. Nuts of fastening of the main cylinder
22. Tank sealant
23. Collar
24. Vacuum amplifier of brakes
25. Knee


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

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

Air removal from the main cylinder

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


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 hydraulic actuator, without applying considerable efforts.
3. Tighten everything the union and a fastening nut with the set moment.
4. Fill the main cylinder with liquid, then pump over it (if preliminary pumping was not carried out), pump over all hydraulic actuator.
5. When pumping cylinder on the car ask the assistant to press several times a pedal and to hold her in the pressed situation. Release the union let's leave to air and liquid, then tighten. Repeat procedure for both unions until then while in brake liquid air vials will not disappear. Check work of brakes before car operation.