Montero Sport LTD 4WD V6-3.5L SOHC (1999)
Vacuum Brake Booster: Testing and Inspection
BRAKE BOOSTER OPERATING TEST
For simple checking of the brake booster operation, carry out the following tests:
1. Run the engine for one or two minutes, and then stop it.
If the pedal depresses fully the first time but gradually becomes higher when depressed succeeding times, the booster is operating properly If the
pedal height remains unchanged, the booster is defective. Go to step 2.
2. With the engine stopped, step on the brake pedal several times.
Then step on the brake pedal and start the engine. If the pedal moves downward slightly, the booster is in good condition. If there is no change, the
booster is defective. Go to step 3.
3. With the engine running, step on the brake pedal and then stop the engine. Hold the pedal depressed for 30 seconds. If the pedal height does not
change, the booster is in good condition, if the pedal rises, the booster is defective. If the above three tests are okay, the booster is OK.
If one of the above three tests is not okay, the check valve, vacuum hose, or booster will be defective. Check the check valve, vacuum hose for
leaks, high volume engine vacuum applied to booster. Repair or replace as necessary. If OK, replace booster and this step starting at Step 1.
