Audi A4

since 1994 release

Manual of the car

Audi A4
+ Running gear
+ Regular servicing
+ Engines
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
- Brakes
   Independent work on the brake system
   So the brake system works
   Check of brakes
   Brake fluid
   Check of level of brake fluid
   Check of the brake system on tightness and existence of damages
   Replacement of brake fluid
   Disk brakes
   Measurement of 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
   Emergency brake
   Check of idling of the lever of the emergency brake
   Main brake cylinder
   Brake amplifier
   Check of the brake amplifier
   Works on hydraulics of the brake system
   Pumping of the brake system
   The help at malfunctions
   ABS and EDS
   What does ABS?
   Function of separate knots
   Electronic system of distribution of brake effort (EBV)
   Violations in work of the ABS system
   Electronic blocking of differential (EDS)
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Lighting
+ 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 thickness of a slip on brakes of back wheels:

1 – slip material;
2 – the bearing plate from metal.

Control of wear of slips on back disk brakes is exercised also as, on lobbies. Here the same maximum permissible size of wear of 7 mm works – it is measured together with bearing slip plate that corresponds to thickness of the slip approximately in 2 mm.

Along with slips the condition of brake disks is checked. The size of wear and the sequence of actions the same that on forward disk brakes.

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

Replacement of overlays of back disk brakes

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


  1. Unscrew both fixing bolts of the case of a brake support, at the same time in an opposite direction wring out the directing finger for a hexagon.
  2. Remove the case of a brake support.
  3. Take out slips from guides.
  4. Install a special key 3272 on the brake piston (the drawing below) and screw up against the stop the piston by rotation of the running screw to the right and a nakatny roller to the left.
  5. Let at the same time your assistant do not lose sight of the level of brake fluid in a tank. If it threatens to pour out, then suck away it the syringe for injections.
  6. Never wring out the piston with a force and without rotation. Otherwise the adjusting mechanism in the brake piston will collapse.
  7. Insert new slips.
  8. Tighten the case of a brake support new самоконтрящимися bolts on 30 Nanometers.
  9. For an extraction of the directing finger in an opposite direction use only a narrow rozhkovy key. The wide key will jam, and the moment of an inhaling will be distorted.
  10. Before the first meters of a trip several times wring out a brake pedal that the normal gap of a pedal was established.

Dismantle of a back brake support

Here by means of a laid on key (3) the lower fixing bolt of the case of a brake support unscrews. The directing finger is wrung out to the opposite side by Rozhkov a key (2). Contrary to Lucas brakes on forward wheels the top fastening is here too weakened (1). 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 – external slip; 2 – internal slip;
3 – the brake piston with the inserted heat-shielding screen.

Sleva: here at the dismantled case of a brake support the brake piston of a back disk brake by a special key 3272 of the 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 replacement of a slip. At the same time surely consider instructions above in the text!
  3. Dismantle cables of the emergency brake.
  4. Weaken 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 not 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 several times press a brake pedal in order that the normal gap of a pedal was established.

Replacement of cuffs of back brake pistons

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

Replacement of a back brake disk


  1. Dismantle a back brake support assembled.
  2. Remove a brake disk.
  3. Clear an adjacent surface of a nave of a wheel or process an emery paper and put a new brake disk.
  4. Carry out new main adjustment.