Air from the brake system is removed by pumping the brake pedal, which requires an assistant.
Attention: The work carried out on a car equipped with ABS and without it are similar. At service stations, air is removed using a special installation connected to the expansion tank. When using this setting on an ABS-equipped vehicle, the brake system is bled of air and applied to the brake pedal.
If you want to remove air from the entire system, the air is removed separately from each cylinder. This is necessary when air enters all cylinders. If only one wheel cylinder has been replaced or repaired, it is usually sufficient to bleed the corresponding brake cylinder.
Air removal sequence:
- 1. Brake caliper rear right.
- 2. Brake caliper rear left.
- 3. Front right brake caliper.
- 4. Brake caliper front left.
Remove boot from brake cylinder bleed valve. Clean the valve, put a clean hose on it, lower the other end of the hose into a vessel half filled with brake fluid.
The vessel must be at least 30 cm above the bleed valve. This prevents air from entering the brake system through the threads of the bleed valve.
Assistant "pump up" brake pedal to pressurize the system. This is felt by the increased resistance when you press the pedal.
When sufficient pressure is generated, press the pedal all the way down and keep your foot on the pedals.
Open the valve about half a turn. Collect the escaping liquid in a container. Make sure that the end of the hose is always below the liquid level in the vessel.
Release the brake pedal and press it about 12 times (pump). In this case, the pedal does not resist. The brake fluid flows through the hose into a container. Hold the brake pedal depressed and have an assistant close the bleed valve.
Repeat the process of removing air from one cylinder until there are no air bubbles in the liquid flowing into the vessel.
After removing the air, remove the hose and put the boot on the valve.
In the same way to remove air from other cylinders.
Attention: In the process of bleeding from time to time, observe the liquid level in the expansion tank. The liquid level must not fall too low, otherwise air will be sucked through the tank. Top up with new brake fluid!
After removing the air, add brake fluid to the expansion tank up to the MAX mark.