A: To check the operation of a power brake booster, depress the brake pedal several times with the engine off and ensure there is no change in the pedal reserve distance. Then, depress the pedal and start the engine. If the pedal goes down slightly, the operation is normal. To check the airtightness of the booster, start the engine and turn it off after one or two minutes. Depress the brake pedal slowly several times. If the pedal depresses less each time, the booster is airtight. Alternatively, depress the brake pedal while the engine is running and stop the engine with the pedal depressed. If there is no change in the pedal reserve travel after holding the pedal for 30 seconds, the booster is airtight. If removal of the power brake booster is necessary, it should not be disassembled and requires special tools. Remove the Brake Master Cylinder and air filter housing, disconnect the vacuum hose from the booster, and unclip or detach any Brake Lines around the booster. Locate the clevis which connects the booster pushrod to the top of the brake pedal and remove the clevis pin retaining clip with pliers. Remove the four nuts and washers holding the brake booster to the firewall and slide the booster straight out from the firewall until the studs clear the holes. Installation procedures are the reverse of removal, with the clevis locknut and booster mounting nuts tightened to the proper torque specifications. If a new power brake booster unit is being installed, the booster pushrod-to-master cylinder piston clearance must be at zero to avoid brake dragging or excessive pedal travel. Finally, adjust the brake pedal height and free play and bleed the system.