Here is a more detailed explanation of how power brakes work:
* Vacuum boosters use the engine's vacuum to create a force that helps you push the brake pedal. When you step on the brake pedal, a valve opens that allows vacuum to flow into a chamber behind the brake pedal. This vacuum creates a force that helps you push the brake pedal down.
* Hydraulic boosters use the car's hydraulic system to create a force that helps you push the brake pedal. When you step on the brake pedal, a piston in the master cylinder pushes hydraulic fluid into a line that leads to the brake booster. The brake booster uses this hydraulic pressure to create a force that helps you push the brake pedal down.
When the engine is off, there is no vacuum or hydraulic pressure available to assist the brake pedal. This means that you have to use more force to stop the car.
It is important to note that power brakes do not completely fail when the engine is off. You will still be able to stop the car, but it will require more effort. If you are ever in a situation where the engine is off and you need to stop the car, be sure to press the brake pedal firmly and gradually.
