Toyota 44610-06472 Booster Assembly, Brake

Perform the following checks on the power brake booster: Depress the brake pedal multiple times with the engine off to ensure the pedal reserve distance remains unchanged. Depress the pedal and start the engine. If the pedal slightly moves down, it's operating normally. For an airtightness check, start the engine and turn it off after a minute or two. Depress the brake pedal slowly multiple times; if the pedal depression lessens with each press, the booster is airtight. Depress the brake pedal with the engine running, then stop the engine while keeping the pedal pressed. If the pedal reserve travel doesn't change after holding it for 30 seconds, the booster is airtight.