9.1.2. Removal of air from a coupling drive hydraulic system

GENERAL INFORMATION

Air needs to be removed from a hydraulic system of the drive of coupling if coupling badly separates at transfer change, the pedal of coupling comes back slowly or does not come back or if the hydraulic system was opened.

As the hydraulic system of coupling uses brake fluid, it is necessary to read the subsection Removal of Air from the brake system.
ATTENTION

Brake fluid is poisonous. Do not suck away liquid a mouth through a hose at all. You store liquid only in capacities, casual access to which is excluded.

PERFORMANCE ORDER
1. Lift and install the car on supports. Remove the lower cover of a motive compartment, at the same time address the subsection Removal and installation of the lower cover of a motive compartment.
2. Check the level of brake fluid in the general tank. If necessary add to the mark Max.
3. Remove boots from the union of removal of air on the working cylinder and on a forward left support.
4. Carefully turn off and wrap the union.
5. Put on a transparent hose the union on a support.
6. Fill a hose with brake fluid. For this purpose open the union on a support. Ask the assistant to press slowly a pedal of coupling and to press in this situation. Close the union and release a pedal. Then open the union again and again press a coupling pedal. Repeat process until the hose is not filled with liquid. Press a hose a finger that liquid did not pour out.
ATTENTION

Do not allow too essential decrease in level of liquid in the tank. Otherwise add liquid....
7. Put on the free end of a hose the union of the working cylinder and open both unions.
8. Press a brake pedal, close the union on a support and release a brake pedal. Repeat this procedure so many time how many it is necessary in order that in the tank there were no air bubbles. At the same time constantly add new liquid.
9. Close unions on a support and the working cylinder. Remove a hose and put on boots.
10. Lower the car on wheels.
11. Fill the tank with brake fluid to the mark Max.
12. Several times press a coupling pedal. Thus, it is possible to check whether the air which remained in system is emitted in the tank.
13. Check operation of the brake system and system of the drive of coupling.
ATTENTION

At the described process of removal of air it can remain in system. It can be determined by a characteristic sound at inclusion of transfer and to bad switching off of coupling. In this case it is necessary to remove air in conditions HUNDRED by means of the special device.
14. Establish the lower cover of a motive compartment, at the same time address the subsection Removal and installation of the lower cover of a motive compartment.
Removal of air by means of the special device
In conditions HUNDRED air from a hydraulic system is removed by means of the special device. This device creates pressure in 2.5 bars upon brake fluid in the tank.
15. Turn off a stopper of the tank of brake fluid. Fill in liquid to the mark Max. Attach the device according to the instruction, not including it.
16. Put on a hose the union of removal of air (the shooter on an accompanying illustration), for example, V.A.G 1238 B/3 of the working cylinder (B). Lower the end of a hose in the capacity filled with brake fluid or connect to device capacity for removal of air.
17. Open the union and you hold its opened until bubbles stop leaving.
18. Several times press a coupling pedal.
19. Fill in liquid in the tank to the mark Max. Screw a stopper on the tank.