See Figures 1 and 2
Vehicles equipped with Anti-Lock Brake Systems (ALB) require separate bleeding procedures if any of the ALB components have been removed or the lines disconnected. Refer to the procedure later in this section.
It is necessary to bleed the hydraulic system any time the system has been opened or has trapped air within the fluid lines. It may be necessary to bleed the system at all four brakes if air has been introduced through a low fluid level or by disconnecting brake pipes at the master cylinder.
If a line is disconnected at one wheel only, generally only that brake circuit needs bleeding; although bleeding all four wheels is always recommended. If lines are disconnected at any fitting between the master cylinder and the brake, the system served by the disconnected pipe must be bled.
On vehicles with rear drum brakes, misadjusted brake shoes can cause a "long" pedal and reduced braking, giving the illusion of air in the lines. If you're trying to track down such a problem, adjust the rear brakes and test drive the car before bleeding the system.
- Fill the master cylinder reservoir to the MAX or FULL line with brake fluid and keep it at least half full throughout the bleeding procedure.
It is strongly recommended that whenever bleeding is required, all wheels be bled rather than just one or two. The correct order of bleeding is:
Prelude: Left front, right rear, right front, left rear
- At the wheel to be bled, place the correct size box-end or line wrench over the bleeder valve and attach a tight-fitting hose over the bleeder. Allow the tube to hang submerged in a transparent container half full of clean brake fluid. The hose end must remain submerged in the fluid at all times.
- Have an assistant slowly pump the brake pedal several times slowly and hold it down.
- Slowly unscrew the bleeder valve ( 1 / 4 - 1 / 2 turn is usually enough). After the initial rush of air and fluid, tighten the bleeder and have the assistant slowly release the pedal.
- Repeat until no air bubbles are seen in the hose or container. If air is constantly appearing after repeated bleedings, the system must be examined for the source of the leak or loose fitting. When you are finished with a wheel, tighten the bleeder screw to 5-7 ft. lbs. (7-9 Nm).
- Periodically check the reservoir on the master cylinder, topping it as needed to maintain the proper level.
- After bleeding, check the pedal for "sponginess" or vague feel. Repeat the bleeding procedure as necessary to correct. Top off the reservoir level.
- Test drive the car to check for proper brake function.