11.8. Pumping of the brake system

You make pumping of the brake system in goggles. At casual hit of brake fluid in eyes immediately wash out them a plentiful amount of water and ask for the help the doctor!


1. Pumping of hydraulic system is made for the purpose of removal from it of the air getting to the highway when performing service of brake mechanisms, replacing hydraulic lines or GTTs, and also when lowering below the minimum admissible value of level of liquid in the tank of the main cylinder. If air got to system owing to falling of level of liquid in the GTTs tank, or at a detachment from GTTs of brake lines, brake mechanisms of all four wheels are subject to pumping.
2. At a detachment of hydraulic lines from any of supports / wheel cylinders there will be only a concrete brake mechanism given to pump over enough.
3. If the detachment of the brake line from the union located between GTTs and one of brake mechanisms was made only this part of a brake contour is pumped over.
4. Each of brake mechanisms is pumped over in an individual order. It is necessary to begin with the most remote (on length of a hydraulic contour) from mechanism GTTs. The order of carrying out full pumping of the brake system is shown on illustrations.

5. Several times squeeze out a pedal of a foot brake at the killed engine for dumping of residual depression in the vacuum amplifier of brakes.
6. Having previously carefully wiped, uncover the GTTs tank, as necessary add fresh liquid to the tank, then enclose polyethylene under a cover and screw it into place.

Do not forget to check regularly liquid level in the tank during pumping performance. Excessive falling of level is fraught with hit in air GTTs that will bring to naught all made efforts and will cause need of pumping of all brake system.

7. Secure with the help of the assistant, prepare a reserve of fresh brake fluid, the transparent vessel which is partially filled with hydraulic liquid, the piece of a plastic hose which is densely put on the pumping gate, and suitable рожковый / a cap key for отпускания / tightenings of gates.

8. The gate of pumping of disk brake mechanisms is located directly on the case of a support, drum - from the back party of a brake board.

9. Having carefully wiped, remove a protective cap and slightly weaken the gate of pumping of the brake mechanism of the corresponding wheel, then again bring up him so that it was easily and quickly released during the procedure.

10. Pull a suitable plastic or rubber hose which second end lower in the transparent vessel which is partially filled with pure brake fluid on the gate. The cut of a hose has to be completely shipped in liquid.

11. Ask the assistant to squeeze out several times slowly a pedal of a foot brake, having lifted thereby pressure in system.
12. At the brake pedal recorded in the lower situation slightly open the pumping gate so that from it brake fluid began to be forced out. You watch a liquid exit from a hose. In couple of seconds when the pressure weakens, close the gate and allow the assistant to release a pedal.
13. Repeat procedures of the last two paragraphs until liquid, free from air bubbles, does not begin to follow from the gate, then pass to the brake mechanism of the left back wheel. Working in a similar manner, pump over mechanisms of the remained car wheels.

Constantly watch that liquid level in the GTTs tank did not fall excessively low!

14. Do not add old brake fluid in the tank at all, - it is hygroscopic in the highest measure and over time absorbs in itself a lot of moisture that leads to falling of a point of its boiling and, as a result, to decrease in efficiency of braking. Besides, presence at hydraulic system of moisture promotes the accelerated aging of material of flexible brake hoses.
15. Upon completion of pumping add fresh brake fluid in the GTTs tank, having normalized its level.
16. Check efficiency of functioning of brakes. The pedal when squeezing has to show firm resistance, - the feeling of softness of its course demonstrates existence in hydraulic contours of air and need of repetition of the procedure of pumping.

Do not start operation of the car at all, being not absolutely sure of serviceability of functioning of the brake system!