10.6. Pumping of hydraulic system

Hydraulic liquid is poisonous; at hit of liquid on skin immediately wash away it a plentiful amount of water. At hit of liquid in eyes immediately see a doctor. Some types of hydraulic liquids are flammable and can ignite at contact with hot components of the engine or naked flame.

During the work with hydraulic system it is always more reasonable to assume that the liquid which is in it is flammable and to take at the same time the appropriate measures of precaution similar to precautionary measures at work with fuel system.

Hydraulic liquid is extremely aggressive for the painted surfaces and plastic details. At casual spilling of hydraulic liquid on the painted surfaces or plastic details immediately wash away it a plentiful amount of water.

Liquid also is hygroscopic (has ability to adsorb moisture from air); excessive liquid moisture content leads to decrease in a point of its boiling to unacceptable value and, as a result, to falling of hydraulic pressure.

Old hydraulic liquid can be polluted and should not be subject to reuse. At a dolivaniye or replacement of hydraulic liquid always use the recommended liquid grades, pouring it from just open tight container. For ensuring access to a drain tube and the gate, remove a viewing cover of the top part of a dome of transmission.

At a rassoyedineniye of hydraulic lines of coupling in the course of repair or service a certain amount of air surely gets to system. Hit of air in any hydraulic system leads to formation of "elasticity" of system that in coupling leads to the weakening of feeling of a pedal and reduction of its course leading to difficulty of gear shifting and even to possible malfunctions of coupling. For this reason before disconnecting hoses of hydraulic lines, it is necessary to press them by means of hose clips, upon completion of work liquid has to be added, and the system is pumped over for removal of air bubbles.


Make sure that pressure in a wheel does not exceed the most admissible value stipulated by manufacturers of set for pumping of system. If necessary pit a part of air from a wheel. Slowly open the air valve and let's be balanced to pressure of liquid and air. Before continuing the procedure, make sure of lack of leaks.

Set for pumping of system of coupling under pressure (in application)

And — Capacity from a set for pumping
In — Connection of supply of liquid on
tank of hydraulic
car liquids
With — the Drain capacity attached to the pumping gate
D — Compressed air moves from a spare wheel


1. For ensuring access to a tube and the gate of pumping of system of coupling, remove a viewing cover in the top part of a dome of transmission.
2. Put on a cap wrench a pumping gate head, however, do not give the gate yet. Put on a piece of a plastic hose a gate head and insert other its end into pure capacity. Add in the capacity of hydraulic liquid so that the end of a hose was hidden by liquid.
3. Working in consent with instructions of manufacturers pour hydraulic liquid in a special vessel from a set for pumping of system of coupling.
4. Unscrew a cover of the tank of hydraulic liquid of the car, then connect to the tank the giving hose from set for pumping of system.
5. Connect a pressure head hose for supply of compressed air - as a source of compressed air the spare wheel can be used.
6. A wrench give the pumping gate so that it became visible how through a drain tube the liquid stream with bubbles comes to capacity. Support an equal stream of liquid until liquid, free from air bubbles begins to arrive; constantly you watch liquid level in a vessel from set for pumping of system and the tank of hydraulic liquid of the car - at too strong falling of level there is a risk of hit of air in system that will nullify sense of the carried-out procedure. For filling of a vessel from set disconnect compressed air, uncover and add in a vessel the required amount of liquid from a fresh container - do not apply the old liquid collected in drain capacity. Continue the procedure before complete cessation of leaving the system of air bubbles.
7. In conclusion several times pump over a brake pedal for installation of feeling of a pedal and its course. In the absence of the constant resistance of a pedal during all its course it is necessary to assume that in system there was an air and to continue the procedure of pumping of system of coupling before installation of normal feeling of resistance of a pedal.
8. Turn off supply of compressed air in a set for pumping of coupling and remove a set from the car. At this stage the tank of hydraulic liquid will be crowded; excess of liquid can be removed by means of a pure tubule, and the level of liquid has to be established on a mark a maximum.
9. A wrench tighten the gate of pumping of coupling and take out drain capacity. Establish a viewing cover on a transmission dome.
10. In conclusion carry out a road inspection of functioning of coupling by switching of all transfers at start of the car from the place and at start from the inclined plane.