Which system uses less brake pedal effort with more effectiveness?

The correct answer, the vacuum booster, enhances braking efficiency by using vacuum pressure to amplify the force applied to the brake pedal. When the driver presses the brake pedal, the vacuum booster harnesses engine vacuum to create a significant mechanical advantage. This means that less effort is required from the driver to achieve the same amount of braking force, resulting in more effective braking with reduced physical input.

The vacuum booster typically operates in conjunction with the master cylinder, ensuring that greater pedal force translates into enhanced hydraulic pressure in the braking system. This amplification allows for smoother and more effective braking, particularly in situations where maximum stopping power is needed.

While other components, such as the spool valve and power piston, are involved in the braking system, they do not necessarily enhance the effectiveness of braking with less pedal effort in the same way that the vacuum booster does. The output rod is also a critical component in connecting the pedal to the master cylinder but does not directly amplify the force applied to the brakes. Hence, the vacuum booster is the most effective in reducing driver effort while maximizing braking performance.