To perform an operating check, depress the brake pedal several times with the engine off, ensuring no change in the pedal reserve distance, and confirm that the booster reserve vacuum is fully utilized. While holding the pedal down, start the engine; the pedal should fall to the floor. Release the pedal, wait a few seconds, and apply it again to check if it returns to its normal position. If it does not, check the vacuum to the booster; if the vacuum is good, the booster is faulty and should be replaced. For an airtightness check, start the engine and turn it off after one or two minutes, then depress the brake pedal slowly several times; if the pedal depresses less each time, the booster is airtight. With the engine off, pump the brake pedal several times to deplete the vacuum in the power brake booster before removal. The booster units should not be disassembled due to the need for special tools; instead, replace them with new or rebuilt units. Disconnect the negative battery cable, remove the windshield wiper motor, cowl, and
Brake Master Cylinder, then disconnect the hose from the engine to the booster, taking care not to damage it. Remove the driver's knee bolster/airbag and the ABS actuator assembly, then take out the pedal return spring and the clevis pin connecting the booster to the brake pedal. Remove the four nuts holding the brake booster to the firewall and slide the booster away until the studs clear the holes. For installation, follow the reverse of removal, ensuring to securely tighten the clevis locknut and booster mounting nuts. If installing a new power brake booster, check the pushrod clearance by measuring the distances from the pushrod to the master cylinder and adjusting as necessary to avoid interference or excessive travel. After installing the master cylinder and brake hoses, adjust the brake pedal height and freeplay, and bleed the system.