Which system uses the vacuum from the engine to increase the input force from the driver to the master cylinder?

The vacuum assist booster is a component that utilizes the engine's vacuum to enhance the driver's input force on the brake pedal, which in turn increases the pressure in the master cylinder. When the driver presses the brake pedal, the vacuum booster amplifies this force, making it easier to apply sufficient braking power with less physical effort. This system is particularly beneficial for providing consistent and responsive braking performance, as it enables a smaller amount of input force from the driver to translate into a larger mechanical force on the brake system.

In contrast, while the hydraulic system is essential for transferring force through brake fluid, it does not inherently increase input force; it functions based on fluid dynamics. The power booster generally refers to any system that aids in braking force, but in the context of vacuum assistance, it is specifically the vacuum assist booster that operates using engine vacuum. The brake system encompasses all components involved in braking but does not focus solely on the method of force amplification through vacuum. Thus, the vacuum assist booster is the correct answer as it specifically describes the mechanism that utilizes engine vacuum to amplify the driver's force effectively.