Bleeding the hydraulic drive of the brake system

The hydraulic brake drive is pumped to remove air that got there when filling with liquid after replacing it or after repairing the hydraulic drive units associated with its depressurization.

Signs of the presence of air in the hydraulic actuator: - an increase in the pedal travel, its "softness" when the pedal is pressed once; - a gradual decrease in the pedal travel with a simultaneous increase in its "stiffness" with repeated pressing of the pedal.

Before pumping the hydraulic drive, it is necessary to find and eliminate the cause of depressurization.

USEFUL ADVICE: If bleeding the hydraulic drive is associated with the repair of any one circuit and the serviceability of the other circuit is known, then bleeding only the repaired circuit is permissible.

The steps for bleeding the hydraulic drive are the same as for replacing the brake fluid (see Brake Fluid Change), the only difference is that the criterion for completing the pumping of the working cylinder is the cessation of the release of air bubbles from the hose, and not the appearance of fresh brake fluid, and before pumping, it is not necessary to remove the old fluid from the reservoir of the master brake cylinder.