Audi A4

since 1994 release

Repair and operation of the car

A4 Audi
+ 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
   Coupling functioning
   Coupling actuating
   Coupling check
   Check of hydraulics of coupling
   The help at malfunctions
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ 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


Check of hydraulics of coupling

In a bell of coupling of the dismantled engine knots of management of coupling are visible

1 – the switching off lever (it is affected by force of the main cylinder of coupling);
2 – vyzhimny bearing;

3 – entrance shaft of a transmission.

Over a coupling pedal (the figure "1" designated the lever) (5) working cylinders of coupling and both fixing bolts are visible a rubber cuff (3 and 4). The figure "2" designated a lock collar of a hinged finger which has to be taken out at dismantle.


  1. If coupling is switched off correctly, its hydraulic system anyway as it should be.
  2. But if it is switched off badly or the pedal fails without resistance, for certain air got to hydraulic system.
  3. Simple removal of air will not help here – it is necessary to find a place of leak and to repair it. Now you can remove air from system. You will find information on other causes of defect of coupling at the end of this chapter in the section Help at malfunctions.
  4. For the purpose of preventive check of hydraulic system of coupling look for traces of brake fluid on the working cylinder (above on a coupling pedal) and on the main cylinder (on a transmission).
  5. The cylinders of coupling moistened with oil are not tight and are subject to replacement. Though the origin of oily dirt on the main cylinder is defined hardly without thorough cleaning of this site.

 Council: The hydraulics of coupling receives the liquid from a tank with brake fluid, but at a leakage in this area danger does not threaten brake system. The liquid intake branch pipe in hydraulic system of coupling is on a tank quite highly therefore for brakes always there is enough liquid.

Dismantle of the working cylinder of coupling


  1. Suck away as much as possible liquid from a broad tank (by means of a big medical syringe).
  2. Dismantle facing of a control panel at the left below (the head Salon).
  3. Enclose an old rag under the working cylinder, disconnect the giving hose and let's flow down to the liquid rest in a rag.
  4. From a motive compartment unscrew a delivery hose to the main cylinder.
  5. Unscrew two fixing bolts with internal hexagons at the working cylinder.
  6. Cast away a lock collar of a hinged finger (connection of a pedal and the working cylinder) back, squeeze out a finger.
  7. Now it is possible to remove the cylinder.
  8. At installation of the new cylinder the rod pressing the piston of the working cylinder has to be adjusted so that the pedal of coupling was about 10 mm above a brake pedal.
  9. Surely track: the returnable spring has to wring out a pedal properly. Thus the pedal in a position of rest should not adjoin above to the arm. Otherwise the piston of the working cylinder in a position of rest will not be able to move to a back emphasis.
  10. For adjustment weaken a lock-nut on a press rod and turn press a rod to the left or to the right round its pivot-center. Then again tighten a lock-nut.
  11. Pump over hydraulic system of coupling.

 Council: The coupling pedal in Audi A4 is supplied with a so-called spring with the top dead point. It helps when pressing a pedal, but after removal of a foot returns it in a starting position. If the pedal does not come back, air or the heavy course of a pedal or a spring got to hydraulic system.

Dismantle of the main cylinder of coupling


  1. Lift and record the forward left side of the car.
  2. Unscrew a delivery hydraulic hose from the main cylinder – be careful, thus brake fluid follows.
  3. Substitute capacity.
  4. Weaken a fixing bolt on the cylinder, take out the main cylinder from the transmission case back.
  5. If it is necessary, help yourself anticorrosive spray and the mounting lever.
  6. Slightly oil surfaces of the case of the new cylinder, grease with MoS2 paste a pusher.
  7. Insert the main cylinder into the case of a transmission and press it until it is possible to screw up fixing bolts in a carving on a transmission (25 Nanometers).
  8. Pump over hydraulic system.

Removal of air from hydraulic system of coupling

Who has no device, ordinary for a workshop, for air pumping, deletes air from hydraulic system of coupling the same as from brake – is almost faultless – the next way:


  1. Open a nipple for production of air on a brake of a forward wheel and a nipple on the main cylinder of coupling approximately on 1,5 turns everyone.
  2. Connect both nipples a hose.
  3. Now several times slowly and carefully press a brake pedal in order that hydraulic liquid from a brake of a forward wheel was wrung out through coupling hydraulics.
  4. Do not press on a pedal with a force, differently the hose will break!
  5. Do not lose sight of liquid level in a broad tank.
  6. If vials of air from hydraulic system of coupling do not come to a broad tank any more, both nipples are screwed up and the hose is removed.
  7. Check the level of brake fluid!