What should the hub axle assembly be checked for during a pre-trip inspection?

During a pre-trip inspection, it's crucial to check the hub axle assembly for several key issues to ensure the vehicle operates safely and efficiently. The correct answer focuses on checking for missing hardware and leaks, which are critical as they can lead to serious mechanical problems if not addressed.

Missing hardware can compromise the structural integrity and function of the axle, potentially leading to brake failure or other significant issues during operation. Similarly, identifying leaks is vital because they can indicate more severe underlying problems, such as bearing failure or oil loss, which can result in further damage and increased maintenance costs.

While corrosion and rust are also important to observe, along with the presence of oil leaks, the most pressing issues directly impacting safety and functionality during a pre-trip inspection are the presence of missing hardware and leaks. Thus, ensuring that both these conditions are checked is essential for preventing potential safety hazards on the road. Choosing the correct answer underscores the importance of focusing on the most critical elements during inspections.