Michigan State Brakes Certification Practice Exam

What result indicates a properly functioning load sensing proportioning valve?

1. Decreased hydraulic pressure when vehicle is loaded

2. Consistent pressure regardless of load

3. Increased hydraulic pressure at rear wheels when vehicle is loaded

4. Increased front wheel braking only

The correct answer is: Increased hydraulic pressure at rear wheels when vehicle is loaded

A properly functioning load sensing proportioning valve adjusts the brake pressure to the rear wheels based on the vehicle's load. When a vehicle is loaded, the weight shifts, and the valve increases hydraulic pressure to the rear wheels to enhance braking effectiveness and improve overall stability. This ensures that the rear brakes engage more effectively under higher loads, which is critical for maintaining balanced braking performance. When the vehicle is unloaded, the valve reduces hydraulic pressure to the rear brakes to prevent rear-wheel lockup and maintain vehicle control. Therefore, the correct answer reflects that the valve is designed to increase hydraulic pressure at the rear wheels when the vehicle is loaded, facilitating safer stopping distances and more effective braking dynamics under varying load conditions.