What should be checked regarding the air compressor during a pre-trip inspection?

The air compressor is a vital component of the braking system in a commercial vehicle, making it crucial to check its condition during a pre-trip inspection. The correct answer emphasizes that the air compressor should be gear-driven and not leaking. A gear-driven compressor is more reliable than other types, ensuring efficient operation of the air system, which is essential for the braking system to function properly.

Additionally, a leaking air compressor can indicate severe issues, such as potential loss of air pressure, which could lead to brake failure. Thus, ensuring that the compressor is free from leaks is critical for the safety of the vehicle and its operation.

While visible oil residue might sometimes indicate lubrication, excessive oil can signal a problem that needs to be addressed. Compressors made of plastic would generally not meet industry standards for safety and durability, as most compressors are designed from robust materials capable of handling high pressure. Missing hardware is a clear sign of neglect that can compromise the compressor's functionality and, subsequently, vehicle safety. Therefore, focusing on the gear-driven aspect and leak checks is vital for effective and safe vehicle operation.