If air has entered the ABS hydraulic system, for safety reasons, the air must be removed by a workshop. This occurs when there is a leak in the hydraulic unit, or if the brake fluid reservoir is empty or if fluid was forgotten to be added to the reservoir when the air was bled.
The air from the brake system is removed by rocking the brake pedal, which requires the help of an assistant.
At service stations, air is removed from the brake system, as a rule, using a special device. With the help of such a device, a pressure of up to 2.0 bar is created in the system through the brake fluid reservoir.
If it is necessary to bleed the entire system, each brake is bled separately.
This is mandatory in cases where air has penetrated into each individual caliper. If only one caliper has been replaced or repaired, it is usually sufficient to bleed the corresponding caliper.
Air removal sequence:
- Rear right caliper.
- Rear left support.
- Support front right.
- Support front left.
1. Remove the dust cap from the bleeder port. Clean the fitting, put a clean hose on it, lower the other end of the hose into a bottle half filled with brake fluid. A suitable hose and container are commercially available.
2. Ask an assistant to press the brake pedal as many times as necessary to create pressure in the system. This is felt by the resistance of the brake pedal.
3. Once the pressure is reached, depress the pedal with your foot and do not release it.
4. Loosen the bleed screw half a turn with a spanner, eg HAZET I968-7 Collect the escaping liquid in a bottle. Make sure that the end of the hose in the bottle is constantly below the liquid level. If the system opens, it is noticeable by the compliance of the brake pedal.
5. As soon as fluid pressure begins to drop, close the fitting.
6. Repeat the process of pumping the system until the system is pressurized. Depress the brake pedal and leave your foot on it. Open the bleed valve. Open the fitting until the pressure starts to drop. Then close the fitting.
7. Repeat the process of removing air until there are no air bubbles in the brake fluid entering the bleed tank.
8. After the pumping process is completed, remove the hose from the fitting and put the protective cap on the fitting.
In the process of bleeding, periodically monitor the reservoir for the brake fluid. The liquid level should not drop significantly. Otherwise, air may enter the system. Add only new brake fluid to the system!
9. Air from other calipers is removed in the same way.
10. After the air removal process is completed, it is necessary to add liquid to the tank to the mark "MAX". Check the condition of the gasket -1- of the reservoir cover.
11. After removing air from the system, when you press the brake pedal, it should not gently go down. If this happens, you should repeat the process of removing air.
- Are the brake lines secured?
- Is the brake hose secured in the holder?
- Are the bleed fittings tight?
- Has sufficient brake fluid been added?
- With the engine running, check for leaks. To do this, press the brake pedal with a force of 200-300 N (20-30 kg) within 10 s. The pedal must not loosen. Check all connections for tightness.
Brake fluid must never be spilled or disposed of with household waste. Local authorities inform drivers about the places of its possible disposal.
12. Finally, apply a few brakes on a road with light traffic. At the same time, it is necessary to perform at least one hard braking using ABS (recognize by the pulsation of the brake pedal).
At the same time, keep an eye on the traffic behind you.