Air from the brake system is removed by pumping with the brake pedal. An assistant is needed for this operation.
If you need to bleed the entire system, then you need to remove air from each brake mechanism individually. This happens when air has entered all the working brake cylinders. If only one brake caliper or only one brake caliper has been replaced or rebuilt, it is generally sufficient to bleed only the relevant brake caliper.
Pumping sequence (vehicles without ABS):
- 1. Brake caliper of the rear right wheel.
- 2. Front left wheel brake caliper.
- 3. Caliper of the brake mechanism of a back left wheel.
- 4. Front right wheel brake caliper.
Attention! The procedure for bleeding the brake system for vehicles with ABS may be different and depends on the type of ABS.
TEVES: Bleeding sequence:
- 1. Front left wheel brake caliper.
- 2. Brake caliper of the rear right wheel.
- 3. Front right wheel brake caliper.
- 4. Caliper of the brake mechanism of a back left wheel.
BOSCH: Bleeding sequence:
- 1. Brake caliper of the rear right wheel.
- 2. Rear left wheel brake caliper.
- 3. Front left wheel brake caliper.
- 4. Front right wheel brake caliper.
Attention! During pumping from time to time check the level of brake fluid in the expansion tank. The level of brake fluid in the reservoir must not be allowed to drop to the limit or that the reservoir was at all «devastated». In this case, air will be pumped into the system. Replenish the amount of brake fluid in the expansion tank, adding only fresh fluid! If the expansion tank has been emptied, then you should contact the workshop for qualified bleeding of the brake master cylinder and ABS.
1. Spray the bleeder fittings with a rust converter and let it work to make the bleeder unscrew more easily.
2. Remove the cap from fitting 1 on the brake caliper of the rear wheel and install a slip spanner on the fitting (see illustration).
11.2 Remove the cap from the fitting 1 on the brake caliper of the rear wheel and install a wrench on the fitting
2 - union nut of the brake pipeline (do not loosen the nut)
Attention! When bleeding the brake mechanisms of the rear wheels with disc brakes, the car must be on wheels. This ensures the functioning of the brake force regulator on the rear axle.
3. Clean the fitting, put a clean hose on it, and lower the other end of the hose into a container half filled with brake fluid. The container for collecting the escaping brake fluid must be at least 30 cm above the bleeder valve. This prevents air from entering the brake system through the threaded connection of the bleeder (see illustration).
11.3 Clean the fitting, put a clean hose on it, and lower the other end of the hose into a container half filled with brake fluid.
4. Ask an assistant to depress the brake pedal to the end («sway») several times until the pressure builds up in the brake system. It is felt by the increase in resistance when the pedal is depressed.
After the appearance of sufficient pressure, the pedal should be squeezed out to the stop and held in this position.
5. Loosen the bleed valve with a wrench about half a turn. Collect escaping brake fluid in a container. Make sure that the end of the hose in the container for collecting the escaping brake fluid is constantly below the fluid level.
6. Close the bleeder valve as soon as the brake fluid pressure in the fluid system decreases.
Attention! Tighten the fitting with a small force of approximately 8 Nm to avoid damaging the threads.
7. Repeat pressurizing the brake system with the brake pedal. Then press the brake pedal down to the stop and hold it with your foot. Open the bleed valve and, as soon as the pressure in the system drops as the brake fluid flows out, close the bleed valve.
8. Repeat pumping the system on one wheel cylinder until no air bubbles appear in the liquid flowing into the container.
9. After removing the air, remove the hose from the bleeder union and close the union with a dust cap.
In the same way, remove the air from the remaining wheel cylinders, while observing the bleeding sequence.
After bleeding is complete, add brake fluid to the expansion tank up to the MAXI mark.
Attention! Make sure that:
- A) brake hoses are securely connected;
- b) brake hoses are fixed in holders;
- V) fittings for bleeding the brake actuator are wrapped;
- G) there is enough brake fluid in the expansion tank.
10. Perform a leak test on the brake system by starting the engine. To do this, depress the brake pedal with a force of 200-300 N (20-30 kg) and hold it for about 10 seconds. The pressure in the system and, accordingly, the resistance of the brake pedal, should not decrease. Check all connections for tightness.
11. Perform several braking on a road with light traffic.