On-Vehicle Inspection

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

   HINT:

   The brake booster is airtight if the distance that the brake pedal can be depressed gradually decreases the more that the brake pedal is depressed.

   If incorrect, inspect the vacuum check valve.

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

   Fig 1: Depressing Brake Pedal

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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 assembly.

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 assembly.

Fig 2: Checking Brake Booster Operation

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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 the 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 Assembly

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002