1990 Ford F-150 Pickup Brake Service (ONLINE REPAIR MANUALS)

All components are serviced as assemblies and should not be disassembled.

COMPUTER MODULE

1990-91 Models

• Disconnect battery ground cable.
• On all models, disconnect wiring harness from RABS module.
• On Bronco II, Ranger and Explorer models, remove module to instrument panel retaining screws behind center of instrument panel.
• On Aerostar models, remove module to instrument panel anti-skid plate retaining screws on lefthand side of engine cover under instrument panel.
• On E-Series models, remove parking brake actuator assembly as follows:
• Loosen adjusting nut at equalizer.
• From inside e...

AEROSTAR

• Disconnect brake warning lamp electrical connector from master cylinder.
• Disconnect hydraulic lines from master cylinder, then remove master cylinder to brake booster retaining nuts and the master cylinder.
• Before installing cylinder, check distance from outer end of master cylinder pushrod to front face of booster assembly using suitable gauge block, Fig. . Pushrod length should be .980-.995 inch. Turn pushrod adjusting screw inward or outward until specified length is achieved.
• Reinstall master cylinder and retaining nuts, reconnect hydraulic lines and brake warni...

Make sure booster rubber reaction disc is properly installed as shown in Fig. , if the master cylinder pushrod is removed or accidentally pulled out. A dislodged disc may cause excessive pedal travel and extreme operation sensitivity. The disc is black compared to the silver colored valve plunger that will be exposed after pushrod and front seal are removed. The booster unit is serviced as an assembly and must be replaced if the reaction disc cannot be properly installed and aligned, or if it cannot be located within the unit itself.

• Disconnect battery ground cable.
• Disconn...

When working on or around brake assemblies, care must be taken to prevent breathing asbestos dust, as many manufacturers incorporate asbestos fibers in the production of brake linings. During routine service operations precautions should be taken to minimize exposure. Do not sand or grind brake linings unless suitable local exhaust ventilation equipment is used to prevent excessive asbestos exposure.

• Wear a suitable respirator approved...

BRAKE DRUMS

Any time brake drums are removed for brake service, braking surface diameter should be checked with a suitable micrometer at several points to determine if they are within the safe oversize limit stamped on the brake drum outer surface. If braking surface diameter exceeds specifications, the drum must be replaced. If braking surface diameter is within specifications, drums should be cleaned and inspected for cracks, scores, deep grooves, taper, out of round and heat spotting. If drums are cracked or heat spotted, they must be replaced. Minor scores should be remove...

Two warning lamps are located on the instrument panel to alert the driver to a system malfunction. The red brake warning lamp is used to indicate conventional brake system malfunctions such as low fluid level, parking brake applied and low vacuum conditions (diesel engines only). The yellow anti-lock system warning lamp is used to indicate proper warning lamp circuit operation (2 second illumination with ignition On or engine cranking). If yellow lamp comes on while vehicle is being driven, it is alerting the driver of an anti-lock system malfunction and yellow lamp can...