What can cause brake fade in an air brake system?

Answer: B — Overheating of brake components due to prolonged or excessive braking.

Brake fade in an air brake system primarily occurs when the components experience overheating due to prolonged or excessive braking. This overheating affects the materials involved in the braking system—such as brake drums, rotors, and brake linings—leading to a reduction in their ability to generate friction. As the temperature rises, the effectiveness of the brake linings diminishes, which can result in a significant decrease in braking performance, making it harder for the driver to slow down or stop the vehicle when needed. This degradation of braking power due to heat is often a result of continuous or heavy braking, such as when descending a long hill or in situations requiring multiple rapid stops. Proper understanding and mitigation of conditions that lead to brake fade are crucial for ensuring safe operation, especially in heavy vehicles equipped with air brakes, where the demands on the braking system can be more severe.