page_title: Power brakes
section_title: Drum brakes
hierarchical_section_title: Power brakes / Components / Drum brakes
caption_attribution_description: English: Test rendering of a drum brake. Français&#160;: Illustration d'un frein à tambour.
context_page_description: Power brakes are a system of hydraulics used to slow down or stop most motor vehicles. It uses a combination of mechanical components to multiply the force applied to the brake pedal by the driver into enough force to actuate the brakes and stop a vehicle that can weigh several tons. The brake pedal is connected to the vacuum booster which is the first step of the force multiplication. The booster passes the force to the master cylinder, which applies a compressive force to a liquid and forces it through the brake lines to the brake calipers. The liquid pushes the brake calipers, which in the case of disc brakes, push against the brake rotor causing friction that slows and eventually stops the rotation of the vehicles wheels. In drum brakes, pistons push two shoes against the brake drum accomplishing the same effect.
context_section_description: Another type of power brake installed in automobiles is called the drum brake. This type of brake, in general, will create some friction that will slow down the wheel. How this works is there is a brake cylinder that connects master cylinder to the drum brake via brake lines that transfer pressure from the master cylinder. When the driver pushes the brake pedal with his/her foot, the pistons inside the cylinder will activate. The activation of this piston will allow two brake shoes located within the drum of the brake to expand, thus generating friction to slow down and stop the wheel. Usually, this brake is located in the rear wheels of the vehicle, while the disk brake is located at the front of the vehicle. A car may also have only drum brakes or disc brakes both front and rear.
caption: The inside of a drum brake with the drum removed to show the internal mechanisms
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