Which of the following factors affects the performance of an air brake system?

The performance of an air brake system is significantly influenced by compressor belt deflection. The air brake system relies on an air compressor to generate the compressed air necessary for operation. If the compressor belt is not properly tensioned, which is indicated by excessive deflection, the efficiency of the compressor can be reduced. This can lead to insufficient air pressure being generated for the braking system, ultimately affecting its performance and responsiveness. Proper adjustment of the compressor belt tension ensures that the air compressor operates effectively, maintaining adequate pressure in the system for optimal braking function.

Though ambient temperature may influence the behavior of compressed air, such as affecting the viscosity of the lubricants or the pressure of the air, it doesn't directly impact the fundamental mechanics of the air brake system compared to how a properly tensioned compressor belt does. Similarly, while brake fluid type is crucial for hydraulic brake systems, air brakes operate differently and do not utilize brake fluid. Lastly, while compressor belt deflection plays a critical role in air generation, belt tension relates more to the mechanical aspect of air delivery than any other factors mentioned.