Vacuum Brake Booster: Service and Repair

Power Brake System Components/Description:

REMOVAL
1. Disconnect the battery ground cables.
2. Disconnect manifold vacuum hose from power brake booster check valve.
3. Apply brake pedal several times to deplete vacuum in power brake booster.
4. Remove brake pressure control valve retaining nut.

NOTE: Do not disconnect brake lines from brake master cylinder.

5. Remove two nuts retaining brake master cylinder to power brake booster assembly, and move brake master cylinder off two mounting studs.
6. If equipped with a manual transmission, disconnect clutch cable routing bracket from body side rail and move cable toward engine and position out of the way.
7. Disconnect accelerator cable at dash panel and accelerator pedal and shaft and position out of the way.
8. Working inside vehicle below dash panel, disconnect wiring connector from stoplight switch. Loosen four power brake booster retaining nuts and bolt retaining pedal support bracket to cowl.
9. Remove hairpin retainer and outer nylon push rod spacer from pedal pin. Slide the stoplight switch off brake pedal pin just far enough for outer arm to clear pin. Remove stoplight switch. Be careful not to damage stoplight switch during removal.
10. Slide the booster push rod and brake master cylinder push rod bushing off the brake pedal pin.
11. Remove the four booster stud nuts that secure the pedal support bracket to the power brake booster and dash panel.
12. Inside the engine compartment, move power brake booster forward until the booster studs clear the dash panel. Rotate front of power brake booster inboard (toward engine) and remove power brake booster by raising up until clear.

INSTALLATION
1. Feed power brake booster into dash panel, starting with smallest dash panel hole. Feed the next stud through the slotted hole and then feed the last two studs through larger holes in dash panel.
2. Working inside vehicle, pull booster studs through holes in the pedal support bracket.
3. Install booster push rod and push rod bushings on brake pedal pin.
4. Hand start four booster-to-dash panel retaining nuts. Do not tighten at this time. Position stoplight switch so it straddles booster push rod with slot toward pedal blade and hole just clearing pin. Slide stoplight switch completely onto pin. Be careful not to bend or deform stoplight switch. Install brake master cylinder push rod spacer on pin, and secure all parts to pin with hairpin retainer. Make sure retainer is fully installed and locked over pedal pin. Connect wiring connector on stoplight switch. Tighten four booster-to-dash panel retaining nuts to 21-29 Nm (16-21 ft. lbs.). Tighten brake pedal support bracket to cowl bolt to 19-26 Nm (14-19 ft. lbs.).
5. Disconnect speed control deactivate switch from adapter on brake pedal arm. Push adjuster mechanism towards the switch pivot. Depress brake pedal. Reconnect speed control deactivate switch to adapter on brake pedal arm. Pull up on brake pedal to complete adjustment of speed control deactivate switch.
6. Connect manifold vacuum hose to power brake booster check valve.
7. Install brake master cylinder assembly to booster studs. Install locking nuts and tighten to 21-29 Nm (16-21 ft. lbs.).
8. Install brake pressure control valve retaining nut. Tighten to 11-16 Nm (9-13 ft. lbs.).
9. Attach accelerator cable to the accelerator pedal and shaft and pedal support bracket. On manual transmission vehicles, secure clutch cable routing bracket to the body side rail.
10. Connect battery ground cable.
11. Bleed brake system. Refer to Hydraulic System.
12. Start engine and check power brake function.