The hydraulic pressure to the brake system is reduced using a ______ system.

• A. Deboosting (pressure-reducing)
• B. Boosting
• C. Bleeding
• D. Lockout Debooster valve

Answer: (A)

The brakes are designed to operate from boosted hydraulic pressure, but that pressure must be scaled down to a level that the wheel brakes can safely use. A deboost or pressure-reducing system sits in the brake control path to take the higher, boosted pressure and reduce it to the appropriate final pressure before it reaches the wheel brakes. This keeps braking force predictable and prevents over-application that could cause tire skidding or brake wear. Bleeding only removes air from the system, and boosting would increase pressure rather than reduce it, while a lockout debooster valve is a special-case device and isn’t the normal means of setting brake pressure. Overall, the correct concept is a deboosting (pressure-reducing) system.