9.3. Pumping of a hydraulic actuator of the brake system

Pumping of a hydraulic actuator of the brake system is necessary for removal of air which can get to system at its repair or replacement of brake fluid, when falling level of brake fluid in a tank of the main cylinder of a brake, at depressurization of system in case of damage of tubes and hoses.
Signs of hit of air in a hydraulic actuator of the brake system:
– by single pressing a pedal — the increased pedal course, its "softness";
– by repeated pressing a pedal — gradual reduction of the course of a pedal with simultaneous increase in its "rigidity".
Before pumping of a hydraulic actuator it is necessary to find and remove the depressurization cause.

Good advice
If pumping of a hydraulic actuator is connected with repair of any one contour and serviceability of other contour is obviously known, then pumping only of the repaired contour is admissible.

Sequence of pumping of brake mechanisms:
– back right;
– forward left;
– back left;
– forward right.
It will be required to you: a key "on 8", a rubber hose, a vessel for collecting brake fluid.
1. Check level and if necessary add brake fluid in a tank of the main brake cylinder to a tag of "MAX".

Prevention
Add brake fluid only of the same brand, as well as at filled in in system.

2. Install the car on an osmotrovy ditch or the elevator.
3. If back wheels are hung out, previously unblock the regulator of pressure of back brake mechanisms, having inserted the screw-driver between a plate and the piston. Do not forget to take out it upon termination of work.
4. Clear of dirt and raise dust the valve of production of air on the brake mechanism from which it is supposed to delete air.
5. Remove a protective cap from the valve of production of air.
6. Put on a rubber hose a head of the valve and ship its end in the pure transparent vessel which is partially filled with brake fluid (the end of a hose has to be shipped in liquid).
7. The assistant has to press a pedal of a brake of 4-5 times sharply (with an interval between pressing 1–2 c). After the last muscleman it is necessary to hold a pedal in the pressed state.
8. Unscrew the valve of production of air on 1/2–3/4 turns. In the liquid following from a hose vials of air will be visible. When liquid ceases to flow from a hose, completely wrap the valve of production of air then the assistant has to release a brake pedal.
9. Repeat operations 7 and 8 until in the following liquid there are no vials of air. At the same time control the level of brake fluid in a tank and if necessary add liquid, without allowing decrease in level tags of "MIN" are lower.
10. Remove a hose, wipe dry the union of the valve of production of air and put on it a protective cap. Pump over brake mechanisms of other wheels if it is necessary.

Notes
Do not reuse the brake fluid merged when pumping.
If pumping of a hydraulic actuator of the brake system is executed insufficiently carefully, then when pressing a pedal at the end of its course the increased "softness" of a pedal will be felt.

Good advice
It is possible to pump over a hydraulic actuator of the brake system without assistant in two ways. The first — the most reliable: order to the turner an aluminum or bronze cover on the main brake cylinder, screw in it the gate from the camera and an additional hose connect to a spare wheel; pressure of air should not exceed 0,05–0,07 MPas (0,5–0,7 kgfs/cm2). The second — not really reliable, but admissible: connect a rubber pear to the union of the wheel cylinder — connection has to be very dense. Squeeze a pear, unscrew the union; when the pear is filled half, wrap the union. Repeat the procedure three-four times. At trial braking check work of brakes.