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

The hydra-boost power brake booster is serviced as a unit.

REMOVAL

• With engine off, depress brake pedal several times to discharge the accumulator.
• Remove master cylinder from brake booster and position up and out of the way. Do not apply booster with master cylinder removed.
• Disconnect three hydraulic lines from booster, then disconnect input pushrod from brake pedal assembly, Fig. .
• Remove booster mounting nuts, then remove booster from vehicle. Do not carry booster by the accumulator and be careful not to drop booster on the accumulator. The snap ring on the accumulator shou...

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...

• Remove caliper and linings.
• Drain brake fluid from caliper housing, then position housing in a vise.
• Pad area between piston(s) and caliper bridge, then apply compressed air to caliper fluid port to remove piston(s). If piston is seized and cannot be forced from caliper, tap lightly around cylinder bore area while applying air pressure. Use caution when applying air pressure, as piston(s) may develop considerable force from pressure build-up.
• Remove and discard molded rubber boot(s) and square cut seal(s) from caliper assembly.
• Thoroughly clean piston(s) and caliper assembly using ...

SERVICE BRAKE

The rear brake shoes, Figs. and , adjust automatically when the vehicle is driven forward or reverse and the brakes are applied sharply several times. Manual adjustment is required only when brake shoes are replaced. When adjusting rear brakes, ensure that parking brake is properly adjusted and that equalizer is operating freely.

With Drums Removed

• With drums removed, clean areas where shoes contact backing plate, then apply suitable lubricant to these contact areas, ensuring that lubricant does not contaminate linings.
• Using suitable brake shoe adjusting gauge, ad...

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...

Bleed primary and secondary hydraulic brake systems separately, bleeding the longest line first on each system. Do not allow reservoir to run dry during bleeding operation. Never reuse fluid that has been drained from the hydraulic system.

• Loosen master cylinder to hydraulic line nuts and wrap shop cloths around tubing below fitting to absorb escaping brake fluid.
• Depress brake pedal slowly forcing air trapped in master cylinder out at fitting.
• Hold pedal down and tighten fittings, then release brake pedal. Releasing brake pedal before fittings are tightened will allow air to ...