Power-assisted brakes are also referred to, by some, as power brakes. Power-assisted brakes are designed to use the power of the engine and/or battery to increase braking power. Power assisted brakes can use hydraulic, vacuum, air pressure or gearbox-drive assistance to reduce the driver’s pedal effort.

Most cars will use the vacuum suspended units which employ a vacuum-powered booster device to provide added thrust to the foot pressure applied. In a vacuum booster system, pressure on the brake pedal pushes forward a push rod connected to the pistons within the master cylinder. At the same moment, the push rod opens the vacuum-control valve so that it closes the vacuum port and seals off the forward half of the booster unit. The engine vacuum line then creates a low-pressure vacuum chamber. Atmospheric pressure in the control chamber then pushes against the diaphragm. The pressure on the diaphragm forces it forward, supplying pressure on the master cylinder pistons.

Hydraulic booster systems usually tap into the power steering pump’s pressure, and use this power to augment pressure to the master cylinder. Electro-hydraulic booster systems use an electric motor to pressurize a hydraulic system which augments pressure to the master cylinder. This allows the vehicle to have power assisted braking even if the engine quits.

Power-assisted braking is great when it functions correctly, so, if for any reason the power assistance is non existent then suddenly it will take a lot more effort to bring the motor vehicle to a halt. This could increase the distance it takes to stop the vehicle which creates a potentially dangerous situation. It is therefore important to keep the power assisted braking system on your vehicle well serviced and checked over frequently.

Thanks to disc brakes, power-assisted braking systems are standard equipment on almost all vehicles today.

We hope that helps answer the question ‘What is What is Power-Assisted Braking?’!

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