Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Audi 80/Avant
+ Technical specification
+ Engines
+ System of production of the fulfilled gases
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
+ System of injection
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
- Brake system
   Check of brake mechanisms
   Brake fluid
   Check of level of brake fluid
   Check of tightness of brake system
   Replacement of brake fluid
   Disk brake mechanisms
   Measurement of thickness of blocks of the disk mechanism
   Control of a condition of brake disks
   Replacement of blocks of disk brake mechanisms
   Drum brake mechanism
   Measurement of brake shoes of the drum mechanism
   Check of the course of a pedal of a brake
   Disk brake mechanism of back wheels
   Measurement of thickness of blocks of back disk brakes
   Check of a free wheeling of the lever of the parking brake
   Main brake cylinder
   Amplifier of brakes
   Check of the amplifier of brakes
   Regulator of brake forces
   Repair of the hydraulic drive of brakes
   Pumping of brake system
   List of malfunctions
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Main brake cylinder

The main brake cylinder is some kind of "chief" in brake system. It is located behind at the left in a motor compartment and gives to supports of brake mechanisms or wheel brake order cylinders about braking. In more detail about its design and functioning it is written at the beginning of this chapter.

Removal of the main brake cylinder


  1. To pump out brake fluid from a compensation tank.
  2. To remove a tank from the main brake cylinder.
  3. To disconnect all brake hoses of the main brake cylinder.
  4. To turn out both fixing bolts of the lower fastening of the main brake cylinder.
  5. At assembly to establish a new sealing ring between the amplifier of the brake drive and the main brake cylinder.
  6. To tighten a fixing nut the moment of 25 N • m.
  7. Before establishing a tank, it is necessary to moisten with brake fluid a sealing stopper of the connecting union of a compensation tank from within.
  8. To remove air from brake system.