3000GT SL V6-2972cc 3.0L DOHC MFI (1997)
Vacuum Brake Booster: Testing and Inspection
BRAKE BOOSTER OPERATING CHECK
For simple checking of brake booster operation, carry out the following tests.
1. Run the engine for one or two minutes, and then turn the engine "OFF."
2. Step on the brake pedal several times with normal pressure. 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 faulty.
3. With the engine stopped, step on the brake pedal several times with the same pressure to make sure that the pedal height will not change. 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
faulty.
4. 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.
5. Brake booster performance is satisfactory if it passes all three operating tests.
6. If the brake booster does not pass all three tests, there may be a fault in the check valve, vacuum hose or in the booster itself.
