Brake System Bleeding - Vehicles With: Standard Brakes
Brake System Bleeding - Vehicles With: Standard Brakes
Service Repair No - 70.25.02
WARNING: If any components upstream of the Hydraulic Control Unit (HCU), including the HCU itself are replaced, the brake system must be bled using the procedure on T4. This will ensure that all air is expelled from the new component(s).
NOTE: Bleeding of the complete brake system must be carried out using the procedures given on T4. Where only the primary or secondary brake circuits have been disturbed in isolation, it should only be necessary to bleed that circuit. Partial bleeding of the hydraulic system is only permissible if a brake tube or hose has been disconnected with only minimal loss of fluid.
WARNING: Do not work on or under a vehicle supported only by a jack. Always support the vehicle on safety stands.
1. Raise and support the vehicle.
2. Check that the brake fluid lines are secure and that there are no signs of a brake fluid leak. If a brake fluid leak is detected, investigate and rectify the cause of the leak before bleeding the brakes.
3. Pump the brake pedal until the brake vacuum assistance is exhausted.
WARNING: Do not allow dirt or foreign liquids to enter the reservoir. Use only new brake fluid of the correct specification from airtight containers. Do not mix brands of brake fluid as they may not be compatible.
CAUTION: Brake fluid will damage paint finished surfaces. If spilled, immediately remove the fluid and clean the area with water.
CAUTION: The brake fluid reservoir must remain full with new, clean brake fluid at all times during bleeding.
4. Fill the brake fluid reservoir to the MAX mark.
^ Disconnect the brake fluid reservoir electrical connector.
^ Remove the brake fluid reservoir cap.
5. Connect T4 to the vehicle, select diagnostic and proceed as directed for bleeding the brake system.
6. Starting at the brake caliper furthest away from the brake master cylinder, loosen the bleed screw by one-half to three quarters of a turn.
7. Install the bleed tube to the brake caliper bleed screw and immerse the free end of the bleed tube in a bleed jar containing a small quantity of approved brake fluid.
CAUTION: The brake fluid reservoir must remain full with new, clean brake fluid at all times during bleeding.
8. With assistance, depress the brake pedal steadily through its full stroke and allow it to return to the rest position. Repeat the procedure until brake fluid, clean and air-free flows into the bleed jar.
9. When brake fluid, clean and air-free flows into the bleed jar, depress and hold the brake pedal down.
CAUTION: Make sure the bleed screw cap is installed after bleeding. This will prevent corrosion to the bleed screw.
10. With the brake pedal fully depressed, tighten the bleed screw to 10 Nm (7 ft. lbs).
11. Fill the brake fluid reservoir to the MAX mark.
WARNING: Braking efficiency may be seriously impaired if an incorrect bleed sequence is used.
12. Repeat the brake bleeding procedure for each brake caliper, following the above sequence.
13. Fill the brake fluid reservoir to the MAX mark.
14. Apply the brakes and check for leaks.
15. Install the brake fluid reservoir cap.
^ Connect the brake fluid reservoir electrical connector.
16. On completion, road test the vehicle and check the brake pedal operation. The pedal travel should be short with a firm feel.