15.4. Replacement of brake fluid and pumping of the brake system


Pumping of brakes is necessary after replacement of brake fluid, and also for removal of the air which got to a hydraulic actuator at repair or replacement of separate knots of the brake system.
We perform work together.
Air is deleted at first from one contour, then from another, beginning every time with the wheel, most remote from the main cylinder.
For pumping of a forward contour we hang out a forward part of the car and we remove wheels.

We remove a rubber protective cap from the flowing union of the right wheel cylinder.

We put on it a hose (better transparent), having lowered its free end in suitable capacity.

The assistant presses a brake pedal three-four times with an interval one-two seconds and holds a pedal of pressed.

Key on "8" we unscrew the flowing union on 1/2–3/4 turns.

At the same time a part of brake fluid and air are forced out in capacity, and the pedal falls to a floor. Vials of air are well visible in a transparent hose or in liquid. We wrap the flowing union then the assistant can release a pedal.
We repeat operation until an exit of vials of air from a hose does not stop.
During removal of air from system it is necessary to watch liquid level in a tank of the main brake cylinder and if necessary to add it.
Similarly we delete air from the brake cylinder of the left wheel.
At full replacement of brake fluid we conduct pumping until from the flowing union new liquid does not go (it lighter).

It is more convenient to carry out pumping of a back contour on a viewing ditch or the elevator.

To exclude influence of the regulator of pressure upon pumping of brakes, we work at the loaded back wheels (posting of the back bridge is not allowed).