S-class W202 Mercedes

1993-2000 of release

Repair and car operation

W202 Mercedes
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Greasing system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. Ignition system
+ 8. Fuel system
+ 9. Transmission
+ 10. Running gear
+ 11. Steering
- 12. Brake system
   12.2. Anti-blocking system – ABS
   12.3. The additional equipment – ASR system
   12.4. Specifications of brake system
   12.5. Overlays of forward brake shoes
   + 12.6. Overlays of back disk brakes
   12.7. Support
   12.8. Forward brake disk
   12.9. Back brake disk
   12.10. Brake liquid
   12.11. Air removal from brake system
   12.12. Brake pipelines / hoses
   12.13. Replacement of brake highways
   12.14. Brake shoes of the parking brake
   12.15. Adjustment of the parking brake
   12.16. Stoplight switch
   12.17. Diagnostics of malfunctions of brakes
   + 12.18. Wheels and tires
+ 13. Body
+ 14. Electric equipment
+ 14.2. Electroschemes

b47c026d b47c026d

12.11. Air removal from brake system


Cars without antiprobuksovochny system ASR


The control electronic device of Mercedes firm is necessary for air removal from brake system of the car with ASR. The device is connected to the diagnostic tip on the right in a motor compartment. By pressing a key air from ASR system automatically is removed.

After each repair of brakes at which the brake system opened, air which surely should be removed from there can get into pressure head pipelines. A sign of availability of air in pipelines of system is lowering of a pedal of brakes by pressing it a foot without notable resistance. In this case it is necessary to eliminate a leakage and to remove air from system.

Air is given by pressing a brake pedal, the assistant is thus necessary still. If it is necessary to remove air from all brake system, it is necessary to delete it from each brake cylinder separately. At regular replacement of brake liquid within maintenance it is necessary to delete air from all four brake cylinders that it did not get into brake system.

Sequence of removal of air:

1. Right back support.

2. Left back support.

3. Forward right support.

4. Forward left support.

If the support was replaced or under repair, as a rule, enough removal of air from the corresponding cylinder. If repair was made at an empty tank for brake liquid, air removal from all brake system is necessary.

Before removal of air unscrew a cover of a tank of brake liquid and fill in brake liquid to "max" mark.


During removal of air watch a tank of brake liquid. Level of brake liquid should not fall too low, differently through a tank air will be soaked up. Always add only fresh brake liquid!

1. Remove a dustproof cap from the valve сапуна a support. Clean the valve, put on a pure hose, and other end of a hose lower in a vessel half filled with brake liquid.
2. Charge to the assistant to press a brake pedal to ("swing"), while in brake system there will be no pressure that is felt on resistance increase by pressing a pedal.
3. When sufficient pressure will be created, completely press a brake pedal and keep it in such situation.
4. Open the valve сапуна on a support wrench turn approximately on a half of turn. Pouring-out liquid collect in a vessel, watch that the hose end constantly was below liquid level in a vessel.
5. As soon as pressure of liquid will decrease, at once close the valve сапуна.
6. Repeat inflating process, pressure will not increase yet. Press down to refusal a brake pedal, hold a foot on a pedal, open the valve screw сапуна, pressure will not fall down yet, and twirl the valve screw.
7. This operation repeat on one brake cylinder until emergence of vials of air in the brake liquid which is flowing down in a vessel will stop. About 80 ml of brake liquid from one brake cylinder should flow out.
8. After the completion of pumping remove a hose from the air valve сапуна, put on a dustproof cap. The valve screw easily tighten with the moment of 7 N of m.
9. As remove air from other brake cylinders.

During removal of air watch a leveling tank. Level of brake liquid should not fall too low, differently through a tank air will be soaked up. Add only fresh brake liquid.

10. After the completion of removal of air add in a tank of brake liquid to "max" mark. Screw up a cover.

Carry out safety control:

      – whether pumping screws are tightened;
      – whether as it should be level of brake liquid;
      – at the working engine make tightness control. For this purpose press a brake pedal with effort from 200 to 300 N (20–30 kg) within about 10 seconds. The pedal should not move. Check tightness of all connections.

11. In summary make some braking on the silent street.