Air Brake Practice Test

If the air brakes on a vehicle generate excessive heat, which of the following can occur?

1. Improved braking performance

2. Complete brake failure

3. Brake fade

4. Accelerated wear

The correct answer is: Brake fade

Excessive heat generated by air brakes can lead to a phenomenon known as brake fade. This occurs when the brake components, such as the brake drums or discs, become too hot, causing a loss of friction between the brake lining and the braking surface. As the heat builds up, the effectiveness of the brakes diminishes, meaning that the driver may find they need to apply more pressure to achieve the same stopping power, or in severe cases, the brakes may feel ineffective altogether. This loss of effectiveness is particularly dangerous in situations where consistent braking is necessary, such as on long downhill grades. Understanding brake fade is crucial for ensuring safety on the road, as it emphasizes the importance of managing brake temperature during operation. Proper braking techniques, including allowing for ventilation and periodic rest for the brakes during extensive use, are important in preventing excessive heat buildup and ensuring reliable braking performance.