Audi A4, S4

since 2000 release

Repair and operation of the car

Audi A4, S4
+ Introduction
+ Governing bodies and methods of safe operation
+ Current leaving and service
+ Engine
+ Cooling systems, heating and air conditioner
+ Power supply systems, release and decrease in toxicity of the fulfilled gases
+ Systems of electric equipment of the engine
+ Manual box of gear shifting
+ Automatic transmission
- Coupling, power shafts and differential
   - Coupling
      General information
      Removal, installation and check of coupling
      Removal and installation of the bearing
      Removal of air from a coupling drive hydraulic system
   + Power shafts of wheels
   + Models with the full drive of wheels
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

Api study abroad National University of Ireland.

Removal of air from a coupling drive hydraulic system

Air has to be removed from a hydraulic system of the drive of coupling if at inclusion of any transfer coupling is badly switched off, the pedal of coupling does not come back or comes back with delay or the hydraulic system was opened.

As the hydraulic system of coupling works at brake fluid, it is necessary to observe the instructions provided in the Section Removal of Air from brake system.

Brake fluid is poisonous. Do not suck away it a mouth through a hose at all. Store brake fluid only in capacities casual access to which is excluded.

Do not allow hit of brake fluid on a check point If it occurred, immediately wipe liquid. Hit of brake fluid on a check point from a magnesian alloy is especially dangerous.

Lifting operation and installations of the car on supports is connected with danger! Therefore before carrying out operation study Poddomkrachivaniye's Section and towage.


  1. Lift and install the car on supports and remove the lower cover if it is available.

Removal of air by means of the special device

On HUNDRED air from a hydraulic system is removed, as a rule, by means of the device. Such device creates pressure (max. 2.5 atm.) in the tank for liquid.


  1. Unscrew screws and uncover the tank of brake fluid. Fill the tank with liquid to MAX mark.
  2. Attach the device for removal of air according to its management, not including it yet.
  3. Open the ventilation valve before turning on the device.
  4. Before removal of air extend a coupling pedal.
  1. On the working cylinder of coupling put on a hose (And) on the ventilation union (the shooter on an accompanying illustration), the union is open. Connect a ventilation hose to a capacity hose for brake fluid.
  1. Turn on the device and let out about 100 cm of the 3rd brake fluid. It corresponds to the volume of a tea cup. At the end of removal procedure air from should not contain bubbles. Tighten the union the moment 4.5nm.
  2. Several times press a coupling pedal.
  3. Fill the tank with liquid to MAX mark. Screw a cover on the tank.
  4. If necessary, repeat process of removal of air.
  5. Establish into place the lower cover of a check point if it was removed.

Removal of air without use of special devices


  1. Check the level of brake fluid in the general tank, if necessary, add liquid to MAX mark.
  2. Remove boots from the union of removal of air on the working cylinder and from a support of a forward left wheel.
  3. Carefully open and close unions for removal of air.
  4. Put on a transparent hose the support union.
  5. Fill a hose with brake fluid. For this purpose open the union on a support. Ask the assistant to press slowly a pedal of a brake and to keep it in this situation. Close the union and release a pedal. Then again open the union and again press a pedal. Repeat process until the hose is not filled with brake fluid. Close a hose a finger that liquid did not follow.

Liquid level in the tank should not fall too low, if necessary add liquid.

  1. Put on the free end of a hose the union for removal of air of the working cylinder of coupling and open both unions.
  2. Press a brake pedal, close the union on a support and release a pedal. Repeat this process so many time, how many is necessary in order that liquid with bubbles did not come to the tank. Thus constantly add liquid.
  3. Close unions on a support and the working cylinder of coupling. Remove a hose and put on boots.
  4. Lower the car on wheels.
  5. Fill the tank with brake fluid to MAX mark.
  6. Several times press a brake pedal. Thereby removal of the remains of air in system in the tank of brake fluid is provided.
  7. Check work of brake system and coupling.

At the process described above in a hydraulic system there can be an air quantity. A sign of it is the gnash at inclusion of transfer and indistinct separation of coupling. In this case immediately remove air by means of the device on HUNDRED.