On-Vehicle Inspection

1. Airtightness check.
   1. Start the engine and stop it after 1 or 2 minutes. Depress the brake pedal several times slowly.

      HINT:

      If the pedal can be depressed to the floor the first time, but on the 2nd or 3rd time cannot be depressed as far, the booster is airtight.

      If incorrect, inspect the vacuum check valve.

      If the vacuum check valve is normal, replace the brake booster assy.

      Fig 1: Depressing Brake Pedal

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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 airtight.

   If incorrect, inspect the vacuum check valve.

   If the vacuum check valve is normal, replace the brake booster assy.

2. Operation 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.

   If incorrect, inspect the vacuum check valve.

   If the vacuum check valve is normal, replace the brake booster assy.

   Fig 2: Depressing Brake Pedal For Operation Check

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Inspect vacuum check valve.
   1. Slide the clip and disconnect the vacuum hose.
   2. Remove the vacuum check valve.
   3. Check that there is ventilation from the booster to engine, and no ventilation from the engine to the booster.

HINT:

If any fault is found, replace the vacuum check valve.

Fig 3: Inspecting Vacuum Check Valve

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002