What is a Drum Brake Composed Of?

3 Answers
VanHope
07/24/25 7:38pm
Drum brakes typically consist of a brake drum, brake shoes, and a wheel cylinder that drives the brake shoes. The brake drum rotates with the wheel, while the brake shoes inside are pushed by the wheel cylinder to press against the inner surface of the drum. The friction-generated torque stops the wheel from rotating, achieving the braking effect. Here is some related information: 1. As one of the two most common types of brakes, drum brakes have a long history. This design was first used in some carriages in 1902, and by the 1920s, it began to be applied to automobiles, which were still a novelty at the time. 2. Drum brakes have a relatively enclosed structure. Therefore, after continuous high-intensity braking, heat buildup inside is more noticeable, and the phenomenon of heat fade is more pronounced compared to disc brakes, which will be discussed later. Additionally, after driving a certain mileage, dealing with brake dust generated by the friction of the brake shoes is another drawback. When the brake drum gets wet, the efficiency of drum brakes is also more significantly affected than that of disc brakes, which will be covered next.
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StJack
08/10/25 9:04am
I often encounter issues with drum brakes when repairing cars. They mainly consist of several key components: the brake drum, which is fixed to the wheel and provides the friction surface; the brake shoes, equipped with friction material, responsible for clamping the drum to brake; the wheel cylinder, which uses hydraulic pressure to push the shoes outward; the return springs, ensuring the shoes retract after release to prevent sticking; the adjuster, which automatically or manually adjusts the gap between the shoes and the drum to ensure even braking; and the anchor pins, helping to position the shoes. If the springs age or the shoes wear unevenly, the brakes may produce noise or respond sluggishly. I recommend checking the shoe thickness and spring elasticity every 20,000 kilometers, especially for models with drum brakes on the rear wheels, to prevent unexpected risks and enhance daily driving peace of mind.
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NoahRose
09/26/25 4:09am
As someone who enjoys tinkering with cars, I find the construction of drum brakes quite intuitive: the core is that round brake drum, which encloses the internal components; the brake shoes press against it, slowing the vehicle through friction; the wheel cylinder uses hydraulic pressure to push the shoes; the return spring pulls the shoes back to their starting position after braking; plus there's an adjuster to handle the clearance. I've driven many older cars, and drum brakes perform decently on rear wheels after rain, but the shoes tend to accumulate dust, leading to reduced efficiency, so keeping them clean is important. Compared to disc brakes, they are lower in cost and simpler in structure, making them suitable for the rear wheels of economy cars. However, during maintenance, remember to check if the wheel cylinder is leaking or if the springs are fatigued—basic tools are enough for preliminary checks.
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