What is a Drum Brake Composed Of?
2 Answers
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.
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.
