Vacuum-operated boosters require periodic inspection of the vacuum hose and case for maintenance. Dismantling and repair should be done by a professional. To check the power booster, depress the brake pedal multiple times with the engine off and ensure there is no change in the pedal reserve distance. Start the engine and depress the pedal, if it goes down slightly, it is operating normally. Depress the pedal with the engine off and if it goes down farther the first time but gradually rises after subsequent depressions, the booster is airtight. If the pedal feels "hard" when the engine is running, there may be an issue with the booster or a vacuum leak. To remove the booster, detach the master cylinder, vacuum hose, brake light switch, and nuts attaching it to the firewall. Installation involves placing the booster on the firewall, connecting the pushrod and brake light switch, and tightening the mounting nuts. Adjustment may be necessary if the pushrod is misadjusted, and a gauge can be used to check the pushrod length. Hydraulically operated boosters require checking the fluid levels, power steering pump belt tension, and inspecting hoses for leaks and restrictions. Perform a functional test of the Hydro-Boost system to check for proper operation. If the Hydro-Boost unit is suspect, it should be tested by a professional and replaced if necessary. To remove the Hydro-Boost unit, discharge the accumulator, remove the master cylinder and hydraulic lines, disconnect the pushrod from the brake pedal assembly, and remove the unit from the firewall. Installation involves placing the Hydro-Boost assembly on the firewall, connecting the pushrod to the brake pedal assembly, and securing the locknuts. Install the master cylinder, connect the fluid pressure, steering gear, and return hoses, and check for leaks. Bleed the power steering system if necessary.
Posted by FordPartsGiant Specialist 
