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

Check of the amplifier of brakes


  1. The engine has to be killed.
  2. To press a pedal of a brake of 10 times.
  3. To hold a brake pedal now completely squeezed out and to start the engine.
  4. At the serviceable amplifier of the brake drive the pedal has to move a little at this moment. If it does not occur, so strengthening of the brake drive is faulty.
  5. Most likely it is necessary to look for malfunction in vacuum system: not tight vacuum hose from an inlet collector to the amplifier of brakes, faulty the backpressure valve in a vacuum hose near the amplifier, a rubber ring between the main brake cylinder and the amplifier or a membrane of the amplifier.
  6. For control of the backpressure valve to disconnect a vacuum hose from the amplifier of brakes.
  7. The purge, but not absorption has to be possible.
  8. The backpressure valve can be got only together with the corresponding vacuum hose.
  9. For replacement of the damaged rubber ring between the main brake cylinder and the amplifier it is necessary to dismantle the cylinder.
  10. The faulty amplifier of brakes is not subject to repair. To replace.

Removal of the amplifier of the brake drive


  1. To remove the main brake cylinder.
  2. To remove a vacuum hose.
  3. To remove a shelf at the left under the dashboard (section Salon).
  4. To remove a hinged finger in a head of a fork of draft of management of the amplifier of brakes.
  5. To turn out samokontryashchiyesya nuts, fastenings of the amplifier of brakes in salon of the car.
  6. Then to remove both nuts of fastening of the amplifier of brakes in a motor compartment.
  7. To remove the amplifier of brakes through a motor compartment.
  8. If the new amplifier is installed, it is necessary to adjust length of his draft of management in the removed state:
  9. The distance between the middle of an opening of a head of a fork and a basic surface with four hairpins has to make 271 mm (the admission of 0,5 mm).
  10. After adjustment thoroughly to tighten a lock-nut.
  11. Before installation to grease a hinged bolt with jellied greasing.
  12. To use only a new clamp for a hinged finger and new samokontryashchiyesya nuts. To establish a new sealing ring between the amplifier of the brake drive and the main brake cylinder.