Bleeding from the hydraulic drive of the working brake system is necessary to remove air, which significantly reduces the braking efficiency. Air can get into the hydraulic drive due to depressurization of the system during repairs, replacement of individual components or brake fluid. The presence of air in the drive is indicated by an increased stroke of the brake pedal and its «softness». Before removing air, check the tightness of all brake drive units and their connections.
Pic. 6.5. Filling with fresh brake fluid
In the process of pumping the brake system, the fluid level should not fall below the middle of the reservoir of the hydraulic drive of the service brake system.
Bleed the brakes in the following sequence:
- 1 - rear right working cylinder of the brake;
- 2 - rear left working cylinder of the brake;
- 3 - front right brake caliper;
- 4 - front left brake caliper.
Raise the vehicle.
Disconnect the brake pipes from the master brake cylinder.
Pic. 6.6. Gently depress the brake pedal
Slowly depress the brake pedal and hold it (pic. 6.6).
Pic. 6.7. Release the brake pedal
Plug the outlet holes of the brake cylinder with your fingers and release the brake pedal (pic. 6.7).
Repeat the operations three to four times.
Pic. 6.8. Bleeding the brake system
Connect the vinyl tube to the wheel brake cylinder bleeder port (pic. 6.8).
Note. Start bleeding from the wheel brake cylinder that is farthest from the master cylinder.
Press a brake pedal several times, then, holding a pedal in the pressed state, weaken an inhaling of the pumping union.
When the brake fluid stops coming out, tighten the fitting, then release the brake pedal.
Tightening torque: 8.3 Nm.
Repeat bleeding operations until air bubbles no longer appear in the outgoing brake fluid.
Repeat the bleeding procedure for each wheel.
Check the brake fluid level in the reservoir and top up if necessary.