A: The operating check for the brake system involves multiple steps. Firstly, depress the brake pedal several times with the engine off to ensure no change in pedal reserve distance. Then, start the engine and depress the pedal, noting a slight downward movement is normal. For an air tightness check, start and stop the engine after a minute or two. Slowly depress the brake pedal multiple times, observing if it goes down further initially but gradually rises after subsequent depressions, indicating an air-tight booster. Additionally, depress the brake pedal while the engine is running and stop the engine with the pedal depressed. If there is no change in pedal reserve travel after holding for 30 seconds, the booster is air-tight. If the power booster needs to be dismantled, it is recommended to have a new or factory-rebuilt unit installed by a professional. To remove the power booster, disconnect the master cylinder and vacuum hose, remove the lower finish panel and air duct, disconnect the brake pedal return spring, and remove the clip and clevis pin. Remove the four mounting nuts and withdraw the booster unit. During installation, check the clearance between the piston and brake pushrod, adjusting if necessary. Finally, install the Brake Booster, connect the brake pedal, and install the Brake Master Cylinder and vacuum hose. Test the brakes carefully before normal operation.