Bleeding the Brake System

Wear protective eyewear when bleeding the brake system. If brake fluid gets into your eyes, flush them immediately with plenty of water and seek medical attention!

PROCEDURE

1. Bleeding the hydraulic system removes air that enters the circuit during brake component service, brake line or master cylinder replacement, or when the fluid level in the master cylinder reservoir drops below the minimum specified level.
2. If air entered the system because the reservoir fluid level dropped, or because brake lines were disconnected from the master cylinder, bleed the brakes at all four wheels. If a line is disconnected from any single caliper/wheel cylinder, it is sufficient to bleed only that brake unit.
3. If a brake line was disconnected from a fitting located between the master cylinder and one of the brake units, bleed only that part of the brake circuit.
4. With the engine off, press the brake pedal several times to release residual vacuum in the brake booster.
5. Remove the master cylinder reservoir cap, add fresh fluid as necessary, then place a piece of polyethylene under the cap and reinstall it.

Check the fluid level in the reservoir regularly during bleeding. Excessive fluid loss may allow air into the master cylinder, which will negate all previous work and require bleeding the entire brake system.
6. Get an assistant, and prepare fresh brake fluid, a clear container partially filled with brake fluid, a length of plastic hose that fits tightly over the bleeder valve, and a suitable open-end/flare-nut wrench to open and close the valve.
7. Loosen the bleeder valve on the left front brake unit slightly, then retighten it so that it opens and closes easily during the procedure.

8. Fit a suitable plastic or rubber hose onto the bleeder valve, and place the other end in a clear container partially filled with clean brake fluid. The end of the hose must be fully submerged in the fluid.

9. Have the assistant press the brake pedal slowly several times to build up pressure in the system.

10. With the brake pedal held down, open the bleeder valve just enough for brake fluid to start flowing out. Watch the fluid flow through the hose. After a couple of seconds, when the flow weakens, close the valve and have the assistant release the pedal.

11. Repeat the procedures in the last two steps until fluid free of air bubbles flows from the valve, then move to the left rear brake unit. Bleed this unit in the same manner, then the right rear and, finally, the right front brake units.

Always make sure the fluid level in the master cylinder reservoir does not drop too low!
12. Never top up the reservoir with used brake fluid. It is highly hygroscopic and over time absorbs a large amount of moisture, which lowers its boiling point and, as a result, reduces braking effectiveness. In addition, moisture in the hydraulic system accelerates aging of the flexible brake hoses.

13. When bleeding is complete, top up the master cylinder reservoir with fresh brake fluid, bringing the level to the specified mark.

14. Check the brake operation. The pedal should feel firm when pressed; a soft pedal indicates air in the hydraulic circuits and the need to repeat the bleeding procedure.

Never operate the vehicle unless you are completely sure the brake system is functioning properly!