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

Measurement of overlays of back disk brakes

Measurement of a thickness of an overlay on brakes of back wheels:

1 – an overlay material;
2 – a bearing plate from metal.

The control of deterioration of overlays on back disk brakes is carried out also as, on lobbies. The same maximum permissible size of deterioration of 7 mm Here operates – is measured together with a bearing plate of an overlay that corresponds to a thickness of the overlay approximately in 2 mm.

Simultaneously with overlays the condition of brake disks is checked. Size of deterioration and sequence of actions the same that on forward disk brakes.

Along with overlays for a back axis four are used also new самоконтрящихся a bolt which, as a rule, are applied on overlays in packing.

Replacement of overlays of back disk brakes

Though this work to spend easily, but it becomes a problem if there is no special key 3272 of workshop Audi. The subsequent description assumes that the workshop will rent you a key or you can make it on the hired sample.


  1. Unscrew both fixing bolts of the case of a brake support, thus in an opposite direction wring out directing finger for шестигранник.
  2. Remove the case of a brake support.
  3. Take out overlays from the directing.
  4. Establish a special key 3272 on the brake piston (drawing below) and screw up against the stop the piston by rotation of the running screw to the right and накатного a roller to the left.
  5. Let thus your assistant does not lose sight of level of a brake liquid in a tank. If it threatens to pour out, suck away its syringe for injections.
  6. Never wring out the piston with force and without rotation. The adjusting mechanism in the brake piston otherwise will collapse.
  7. Insert new overlays.
  8. Tighten the case of a brake support new самоконтрящимися bolts on 30 Nanometers.
  9. For отжима a directing finger in an opposite direction use only narrow рожковый a key. The wide key will jam, and the inhaling moment will be deformed.
  10. Before the first metres of a trip some times wring out a brake pedal that the normal backlash of a pedal was established.

Dismantle of a back brake support

Here by means of an unprofitable key (3) the bottom fixing bolt of the case of a brake support unscrews. The directing finger is wrung out in an opposite side рожковым by a key (2). Contrary to brakes Lucas on forward wheels the top fastening (1) is here too weakened. At installation use new самоконтрящиеся fixing bolts!

On the right: at the dismantled case (4) supports of a brake of a back wheel are visible: 1 – an external overlay; 2 – an internal overlay;
3 – the brake piston with the inserted heat-shielding screen.

At the left: here at the dismantled case of a brake support the brake piston of a back disk brake by a special key 3272 of workshop Audi is screwed up.


  1. If the brake support has to be replaced, dismantle a brake hose.
  2. Dismantle the case of a brake support, as for overlay replacement. Thus necessarily consider instructions above in the text!
  3. Dismantle cables of a manual brake.
  4. Loosen the both fixing bolts of the brake support still fixed on an axis.
  5. Before installation clean corrugated surfaces under a head of fixing bolts (corrugated bolts).
  6. Use only the provided corrugated bolts, but at all the usual.
  7. At installation tighten fixing bolts of a brake support on 65 Nanometers.
  8. At installation of the case of a brake support observe the instructions described above.
  9. Before the first trip some times press a brake pedal that the normal backlash of a pedal was established.

Replacement of cuffs of back brake pistons

On replacement of defective cuffs of brake pistons of back supports the same order, as for lobbies extends.

Replacement of a back brake disk


  1. Dismantle a back brake support in gathering.
  2. Remove a brake disk.
  3. Clear an adjoining surface of a nave of a wheel or process an emery paper and put a new brake disk.
  4. Spend new basic adjustment.