On-Vehicle Inspection

INSPECT BRAKE BOOSTER
1. Air tightness check.
  1. Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly.
    HINT:
    
    If the pedal goes down farthest the 1st time, but gradually rises after the 2nd or 3rd time, the booster is air tight.
  2. Depress the brake pedal while the engine is running, and stop the engine with the pedal depressed.
    HINT:
    
    If there is no change in the pedal reserve distance after holding the pedal for 30 seconds, the booster is air-tight.
2. Operating check.
  1. Depress the brake pedal several times with the ignition switch OFF and check that there is no change in the pedal reserve distance.
  2. Depress the brake pedal and start the engine.
    HINT:
    
    If the pedal goes down slightly, operation is normal.
INSPECT VACUUM CHECK VALVE
1. Check vacuum check valve.
  1. Slide the clip and disconnect the vacuum hose.
  2. Remove the vacuum check valve.
    
    Fig 1: Inspecting Brake Booster
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    
    Fig 2: Depressing Brake Pedal Several Times
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  3. Check that there is ventilation from the booster to engine, and no ventilation from the engine to the booster.
  4. If any fault is found, replace the vacuum check valve.
  Fig 3: Replacing Vacuum Check Valve
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002