Celica Liftback L4-122 1998cc 2.0L DOHC Turbo (3S-GTE) (1992)
Vacuum Brake Booster: Component Tests and General Diagnostics
Air Tightness Check
AIR TIGHTNESS CHECK
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Start engine and stop after one or two minutes.
Fig. 3 Air Tightness Check
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Depress brake pedal several times slowly. If pedal drops the most on the first time, but gradually rises after the second or third time, booster is air
tight.
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Depress brake pedal with engine running, then while depressing brake pedal stop engine.
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If there is no change in pedal reserve travel after holding pedal for 30 seconds, the booster is air tight.
Operating Check
OPERATIONAL TEST OF BRAKE BOOSTER
NOTE: If there is leakage or lack of vacuum, repair before testing. If available, use a brake booster tester to check the booster operating
condition.
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Depress brake pedal several times with engine stopped, and ensure that pedal reserve distance does not change.
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Depress brake pedal and start engine. If pedal drops slightly, operation is normal.