Ford Expedition 1998 Workshop Manual page 2

1998 Expedition/Navigator Workshop Manual
Four Wheel Anti-Lock Brake System (4WABS)
WARNING: Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with eyes. Wash hands thoroughly after handling. If brake fluid contacts eyes, flush
eyes with running water for 15 minutes. Get medical attention if irritation persists. If taken internally, drink water and induce vomiting. Get medical attention immediately.
CAUTION: Do not allow the brake master cylinder reservoir to run dry during the bleeding operation. Keep the brake master cylinder reservoir filled with the specified
brake fluid. Never reuse the brake fluid that has been drained from the hydraulic system.
CAUTION: Brake fluid is harmful to painted and plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water.
NOTE: When any part of the hydraulic system has been disconnected for repair or new installation, air may get into the system and cause spongy brake pedal action. This requires bleeding
of the hydraulic system after it has been correctly connected. The hydraulic system can be bled manually or with pressure bleeding equipment.
NOTE: This procedure must be performed if the 4 wheel anti-lock brake (4WABS) hydraulic control unit (HCU) has been installed new.
NOTE: One conventional pressure bleed cycle consists of advancing the brake pedal to its depressed position, opening the disc brake caliper bleeder screw, allowing fluid to be released
into the waste container, closing the disc brake caliper bleeder screw and releasing the brake pedal.
NOTE: Performing the NGS program routine drives entrapped air from the otherwise inaccessible lower section of the 4WABS valve into the upper sections (accessible by bleeding the
brakes). Subsequent bleedings remove the air from the system.
NOTE: Add recommended brake fluid as necessary throughout the procedure.
1. Connect a clear waste line to the RH rear disc brake caliper bleeder screw and the other end in a container partially filled with recommended brake fluid.
2. Have an assistant pump the brake pedal and then hold firm pressure on the brake pedal.
3. Loosen the RH rear disc brake caliper bleeder screw until a stream of brake fluid comes out. Have an assistant maintain pressure on the brake pedal while tightening the RH rear
disc brake caliper bleeder screw.
Repeat until clear, bubble-free fluid comes out.
Refill the brake master cylinder reservoir as necessary.
4. Tighten the RH rear disc brake caliper bleeder screw.
5. Repeat Steps 1, 2, 3, and 4 for the LH rear disc brake caliper bleeder screw, RH front disc brake caliper bleeder screw, and the LH front disc brake caliper bleeder screw.
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12/19/2010