Bleeding Brake System
WARNING:
If any components upstream of brake modulator, including the modulator itself are replaced, the brake system must be bled using the procedure on TestBook/T4, to ensure that all air is expelled from the new component(s).
WARNING:
Do not allow brake fluid to come into contact with eyes or skin.
NOTE:
Bleeding of the brake system can be carried out using the procedures given on Textbook/T4, or by following the manual procedure given below.
NOTE:
Following procedure covers partial bleeding of the system. Bleeding could be performed where only the primary or secondary circuit have been disturbed in isolation. It should only be necessary to bleed the disturbed system. This partial bleeding of the hydraulic system is only permissible if a brake pipe or hose has been disconnected with only minor loss of fluid.
NOTE:
Ensure fluid in reservoir is maintained between MIN and MAX levels and NEW brake fluid is used throughout the bleeding procedure.
- Raise and properly support vehicle on jack stands.
- Ensure that all lines and connections are tight and no leaks are present.
- Fill brake fluid reservoir to MAX level with NEW DOT 4 brake fluid.
- Obtain a clean transparent bottle containing a small amount of clean brake fluid and a bleed hose.
- Attach bleed hose to the first brake caliper bleed screw in sequence. See Fig 1. Ensure free end of hose is submerged in the clean brake fluid. See Fig 2.
- Apply pressure to brake pedal several times, then apply steady pressure.
- Loosen bleed screw to release brake fluid and air. Allow pedal to return unassisted.
- Depress brake pedal steadily through its full stoke and allow to return unassisted. Repeat procedure unit a flow of clean, air-free fluid is purged into container. Then while holding pedal at end of its downward stroke, tighten bleed screw to specification. See TORQUE SPECIFICATIONS . Fill brake fluid reservoir to MAX level with NEW DOT 4 brake fluid.
- Repeat procedure for the other 3 brake calipers in sequence. See Fig 1.
- Remove tube from bleed screw and install bleed screw dust cap. Apply brakes and check for leakage. Road test vehicle. Check brake pedal for short firm travel when brakes are applied.