Brake System Bleeding Ford Cab & Chassis Ranger

DESCRIPTION

Brake system bleeding is necessary any time air has been introduced into brake system. Bleed brakes at all four wheels if master cylinder lines have been disconnected or master cylinder has run dry.

Bleeding may be done either by using pressure bleeding equipment or by manually pumping brake pedal and using bleeder tubes. After bleeding, pressure differential control valve must be centered.

MASTER CYLINDER BLEEDING

Note. Master cylinder can be bled on vehicle or by using bench bleeding method.

On Vehicle Bleeding

1. Loosen one line nut on master cylinder. Wrap shop cloth around tubing below bitting to absorb escaping brake fluid. Depress brake pedal to floor by hand and hold. Tighten fitting.
2. Release brake pedal. Do not release pedal until fitting is tightened or air will re-enter master cylinder. Repeat procedure until air no longer escapes from master cylinder. Repeat process for other line and ensure that brake pedal is firm.

Bench Bleeding

Note. Bleed tubes must have a residual pressure check valve installed to keep tubes from siphoning brake fluid.

1. Clamp master cylinder in vise by mounting flange. Install bleed tubes in outlet ports. Fill reservoir with clean brake fluid so that bleed tubes are below brake fluid level. (Scheme 26)
2. Slowly compress and release piston assemblies until bubbles cease to appear in brake fluid. Remove tubes and plug master cylinder outlets to keep fluid from draining.

Scheme 26

MANUAL BLEEDING

Note. DO NOT allow master cylinder to run dry during bleeding. NEVER reuse brake fluid that has drained from brake system. When bleeding disc brakes, air may tend to cling to caliper walls. Lightly tap caliper while bleeding to aid in removal of air.

1. Attach bleeder hose to right rear wheel cylinder and submerge end of hose in container partially filled with clean brake fluid. Loosen fitting about 3/4 turn and slowly depress brake pedal fully. Close bleeder and release brake pedal. Repeat until fluid is free of air bubbles.
2. Repeat process for left rear wheel cylinder, right front caliper and left front caliper in that order. After completing bleeding procedure, center pressure differential valve by depressing brake pedal fully.

PRESSURE BLEEDING

Note. NEVER reuse brake fluid that has drained from brake system. Ensure bleeder tank has sufficient fluid to complete bleeding procedure. DO NOT exceed 50 psi of pressure in tank.

1. On power brake equipped vehicles, release vacuum from booster by depressing brake pedal several times. Clean master cylinder cap and surrounding area. Remove cap. With pressure tank at least 1/2 full, connect to master cylinder with adapters. Attach bleeder hose to right rear wheel cylinder.
2. Place other end of hose in clean container partially filled with clean brake fluid so end of hose is submerged in fluid. Open release valve on pressure bleeder. Follow equipment manufacturers pressure instructions unless noted below.
3. Unscrew bleeder valve 3/4-1 turn noting fluid flow. When fluid flowing from cylinder to jar is free of bubbles, close bleeder valve securely. Bleed left rear, right front and left front in that order and in the same manner. Remove tool from control valve. Center pressure differential valve by depressing brake pedal fully.

PRESSURE BLEEDER SETTINGS

BLEEDING SEQUENCE

BLEEDING SEQUENCE

CENTERING PRESSURE DIFFERENTIAL CONTROL VALVE

1. After repairs or bleeding of either primary or secondary brake system, the brake warning light will usually remain on because the pressure differential control valve is in an off-center position.
2. Ensure brake fluid level in master cylinder is within 1/4 inch of top of reservoir. Turn ignition switch to the ACC or ON position. Depress brake pedal and valve piston will center itself causing warning light to go out.