What is the purpose of the return spring in a drum brake system?

The return spring in a drum brake system serves the essential function of releasing the brake after the braking force has been applied. When the brake pedal is engaged, it activates the brake shoes, pressing them against the drum and creating the necessary friction for stopping the vehicle. Once the driver releases the brake pedal, the return spring pulls the brake shoes back to their original, disengaged position, allowing the drum to rotate freely again. This retraction is vital for preventing drag and ensuring that the brakes do not stay engaged, which could lead to overheating and premature wear of the braking components. The other options, while related to braking performance and vehicle dynamics, do not describe the primary role of the return spring within the brake system.