- put on the head of the fitting 1 (pic. 90) rubber hose 2 for draining the liquid, and lower its free end into a transparent vessel 3, partially filled with liquid;
- sharply pressing the brake pedal 3-5 times at intervals of 2-3 s, unscrew the fitting by 1/2-1/3 turn with the pedal depressed. Continuing to press the pedal, expel the liquid in the system together with air through the hose into the vessel. After the pedal reaches the front end position and the outflow of fluid through the hose stops, tighten the air outlet fitting until it stops. Repeat these operations until the air outlet from the hose stops;
- while holding the pedal depressed, tighten the fitting until it stops and remove the hose. Wipe the hose dry and put on the protective cap;
- repeat the operations for other wheels, first on the second wheel of the same circuit, and then successively on both wheels of another circuit.
Pic. 90. Removal of air from the hydraulic drive of the brakes:
1 - fitting for pumping; 2 - hose; 3 - vessel with brake fluid.
When removing air, monitor the presence of liquid in the tank, not allowing its bottom to be exposed, as this will again allow air to enter the system. If there is no air in the brake actuator, the brake pedal should travel about 1/2 of its full travel. To eliminate the influence of the vacuum booster on the pumping of the brakes, remove the air with the engine off.
If there is no brake fluid in the hydraulic drive, fill the system as follows:
- unscrew the fittings on the cylinders of all wheels by 1.5-2 turns;
- sharply pressing the brake pedal and gently releasing it, tighten the fittings after the fluid begins to flow out of them. Then bleed the system.
When removing air on a car whose brake system has worked for more than 75,000 km, replace the existing fluid with a new one.