Mercedes of the S-class W202

1993-2000 of release

Repair and operation of the car

Mercedes W202
+ 1.2. General information
+ 2. Maintenance
+ 3. Engines
+ 4. Lubrication system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. System of ignition
+ 8. Fuel system
+ 9. Transmission
+ 10. Running gear
+ 11. Steering
- 12. Brake system
   12.2. Anti-blocking system – ABS
   12.3. The additional equipment – the ASR system
   12.4. Specifications of the brake system
   12.5. Overlays of front 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 fluid
   12:11. Removal of air from the 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. Electrical circuitries

12. Brake system

12.1. Introduction


The brake system with ABS and ASR

1. RPM meter
2. Hydraulics block
3. Forward brake mechanism
4. Main brake cylinder
5. Amplifier of brakes
6. Cable of the parking brake
7. Parking brake drums
8. Back brake disks

The hydraulic brake system with the foot drive consists of the main brake cylinder, the hydraulic booster of brakes and disk brakes of forward and back wheels. The brake system has two contours. One of contours covers forward wheels, the second – back. At failure of one of contours, for example, owing to leakage, the car can be slowed down by means of only the second contour. Pressure in both contours is created in the dual main brake cylinder by pressing a brake pedal.

The tank with brake fluid is over the main brake cylinder and provides with brake fluid all system.

The hydraulic booster of brakes accumulates a part of the absorption depression received by means of the engine. As in the diesel absorption depression sufficiently is not formed, models with the diesel have the special pump of depression for the brake system. In this case the effort by means of depression is transferred to brakes via the corresponding valve.

Forward disk brakes are equipped with the disk mechanism with a floating bracket. In this case only one piston is necessary to press both brake slips to a brake disk. On the back bridge there are brake mechanisms with the fixed bracket which provide the required delay. Pressing of brake slips in case of the mechanism with the fixed brackets requires two pistons.

The parking brake is given by means of a cable and influences only back wheels. As disk brakes not really well approach as parking, on back wheels two brake drums which are built in brake disks are in addition placed. Brake drums are involved only for the parking.

When cleaning the brake mechanism dust of wear of slips which is noxious to health flies. Therefore when cleaning brakes you watch to inhaling products of wear of brakes. Brake slips are a component of "Permission to operation of the car in these conditions", besides, they differ depending on model. It is recommended to apply only company brake slips.

Instruction: after installation of new slips they have to be earned extra. During a running in (about 200 km) avoid without the need for sharp braking.

Work on the brake system demands careful purity and exact respect for technology. If experience is absent, address in a workshop.


If when braking, especially on turns, various course of a pedal is felt, then it is necessary to check brake disks for a side beating on outer diameter. Too big side beating can be caused by the raised side play of bearings. Therefore before check this side play and if necessary establish it. If sufficient improvement is not felt after that, replace a brake disk.