Arizona Air Brakes CDL Practice Test

What do brake drums do?

1. Are bolted to the wheels

2. Are located at each end of the vehicle's axles

3. Hold the brake shoes and linings

4. All of the above

The correct answer is: All of the above

Brake drums are critical components of a vehicle's braking system, particularly in drum brake systems. They serve multiple functions that encompass the aspects mentioned in the question. Firstly, brake drums are indeed bolted to the wheels, enabling them to rotate with the wheel and participate directly in the vehicle’s deceleration. This connection allows the drum to effectively interact with the brake shoes. Additionally, brake drums are located at the ends of the vehicle's axles, where they are positioned to receive the braking force applied by the brake shoes. This placement ensures that the force is transmitted effectively, allowing for efficient stopping power. Finally, brake drums are designed to hold the brake shoes and linings. When the driver applies the brakes, the shoes are pushed outward against the inner surface of the drum, creating friction that slows down the vehicle. The effective integration of these parts is crucial for reliable braking performance. Thus, the option that states "All of the above" is correct because it encompasses the full range of the brake drum's functional attributes. Understanding this multi-faceted role helps in grasping how a vehicle's braking system operates as a whole.