9.11. Pumping of the brake system

Replacement of brake fluid



Signs of presence of air at the brake system: after repair the pedal of a brake moves to the floor or at operation prozhimatsya with failures; the pedal course very long also becomes shorter after repeated pressing. Pumping of the brake system needs to be carried out after any repair of a hydraulic actuator of brakes. At an effluence of brake fluid air will surely get to system. It is necessary to pump over the brake system on cars with the ESP system on STOA. For this purpose in the ESP control unit the program of pumping is started.
On STOA brakes are pumped over by means of the special device, but it is possible to execute this operation and a traditional way.

SEQUENCE OF WORKS
1. Note the level of brake fluid in a tank.
2. Add new brake fluid in a tank and during the whole time of performance of work in due time add it as required. Otherwise again will get to system air and work it is necessary to begin again.
3. Remove a rubber cap from the union of pumping of the working brake cylinder of a back right wheel.

Fig. 8.21. Pumping of the brake mechanism of a forward wheel


4. Clear the union nipple, put on it a pure transparent plastic hose and lower its free end in the capacity (a plastic bottle) half filled with brake fluid (fig. 8.21).
5. Carefully unscrew the pumping union a ring key half way.
6. Ask the assistant to press slowly a brake pedal against the stop to extort brake fluid and the air which is in it from system. At the same time you watch a hose and container with brake fluid — you have to notice the vials of air leaving liquid. Detain a brake pedal in the pressed situation.
7. Close the pumping union then remove a leg from a pedal. So air will not get through an union carving to system. Release a pedal slowly.
8. Repeat this operation until in liquid vials of air do not cease to be allocated — it means that air is removed from system. Constantly watch the level of brake fluid in a tank. Finally wrap the union (with a force do not tighten) and put on a rubber cap the union.
9. On other unions of pumping repeat the same operation in the following order: left back wheel, right forward and then the left forward.
10. If in system there was a lot of air, repeat all procedure once again.
11. Upon termination of works double-check liquid level in a tank and if necessary add fresh liquid to appropriate level.
12. Check work of brakes during a trial (careful) trip.