Audi A4

Since 1994 of release

Repair and car operation

Audi А4
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ Exhaust system
+ Cooling system
+ Fuel tank and the fuel pump
+ The air filter and channels всасывания
+ Injection system
+ Coupling
+ Transmission and the main transfer
+ Suspension bracket of wheels and steering
- Brakes
   Independent work on brake system
   So the brake system works
   Check of brakes
   Brake liquid
   Check of level of a brake liquid
   Check of brake system on tightness and presence of damages
   Replacement of a brake liquid
   Disk brakes
   Measurement of a thickness of overlays of forward disk brakes
   Check of a condition of brake disks
   Replacement of overlays of disk brakes
   Back disk brakes
   Measurement of overlays of back disk brakes
   Manual brake
   Check of idling of the lever of a manual brake
   The main brake cylinder
   The brake amplifier
   Check of the brake amplifier
   Works on hydraulics of brake system
   Prorolling of brake system
   The help at malfunctions
   ABS and EDS
   What does ABS?
   Function of separate knots
   Electronic system of distribution of brake effort (EBV)
   Infringements in system ABS work
   Electronic blocking of differential (EDS)
+ Wheels and tyres
+ The electrotechnical equipment
+ Ignition system
+ Illumination
+ The alarm equipment
+ Tools and devices
+ Heating and ventilation
+ Body details
+ Salon
Search of malfunctions
Technical characteristics

Check of the brake amplifier

Area round the brake amplifier with the engine of 1,6 l: 1 – a tank with a brake liquid; 2 – the brake amplifier; 3 – a vacuum tube from an inlet collector; 4 – эжектор for strengthening of the lowered pressure

The same kind, as in a photo above, but with the six-cylinder engine: 1 – a tank with a brake liquid; 2 – the brake amplifier; 3 – a vacuum tube from an inlet collector; 4 – the returnable valve in a vacuum tube


  1. The engine should be switched off.
  2. Press a pedal of a brake of 10 times.
  3. Hold a pedal wrung out and start the engine.
  4. If the brake amplifier is serviceable, the pedal should move a little. If the pedal does not fall, the brake amplifier is faulty.
  5. At failure of the brake amplifier defect, most likely, is covered in system of the lowered pressure: негерметичен a vacuum hose from an inlet collector to the brake amplifier, негерметичен the returnable valve in a vacuum hose, defect in a rubber ring between the main brake cylinder and a servo-drive or a membrane brake usili-telja.
  6. For check of the returnable valve remove a vacuum hose from the servo-driver.
  7. It is blown, отсасывание is inadmissible.
  8. The returnable valve is on sale only together with a vacuum hose.
  9. To replace the damaged rubber ring between the main brake cylinder and the amplifier, it is necessary to dismantle the cylinder.
  10. In summary there is still a defect of the most brake cylinder. In this case repair is impossible – it is necessary to replace it.

Dismantle of the brake amplifier

For easing of a rod of brake pressure upon pedals of brake Audi uses the special tool 3289. Unfortunately, without this tool it is impossible to manage. Sequence of actions:


  1. Dismantle the main brake cylinder.
  2. Dismantle a vacuum hose.
  3. Unscrew two fixing bolts of the brake amplifier (TORX T45).
  4. Dismantle a pocket at the left under a control panel (the head Salon).
  5. Disconnect on a pedal of a brake the switch of fires of stoplights and valves of ventilation of system of adjustment of speed.
  6. Establish on the lever of a pedal of a brake the special tool 3289. Now it is possible to disconnect press a rod of the brake amplifier from a pedal (pull a pedal back).
  7. Take out the brake amplifier from an impellent compartment.
  8. If the new brake amplifier the length of a rod of its management needs to be adjusted in the dismantled condition is established.
  9. The distance between the end of a rod of management (it should stand vertically) and an adjoining surface with two cut apertures should make 158,5 mm (the admission of 0,5 mm).
  10. After adjustment tighten a counternut.
  11. Before installation slightly grease шарнирный a finger.
  12. Use a new clamp for шарнирного a finger and new самоконтрящиеся nuts. Put a new sealing ring between the brake amplifier and the main brake cylinder.