Which technician suggests that a leaking booster check valve is the cause for a hard brake pedal when the engine is off?

• A. Technician A
• B. Technician B
• C. Both Technicians
• D. Neither Technician

Answer: (B)

A leaking booster check valve can indeed lead to a hard brake pedal when the engine is off because this valve is responsible for maintaining vacuum in the brake booster. The brake booster uses engine vacuum to provide assist when applying the brakes, making it easier to press the pedal down.

When the engine is not running, and the check valve is leaking, the vacuum pressure that should be held in the booster dissipates. As a result, the pedal becomes significantly harder to press since there is no longer any power assist available. Technician B's assertion acknowledges this mechanism properly, linking the condition of the booster check valve directly to the performance of the brake system in relation to engine operation.

Technician A may not be suggesting the correct reasoning or details needed to connect the leaking check valve to the hard brake pedal scenario, which would explain why only Technician B's perspective is accurate in this instance.