During a pre-hill inspection of a vehicle with air brakes, what checks should be performed?

In a pre-hill inspection of a vehicle equipped with air brakes, it is essential to ensure the system is functioning properly for safety reasons. Ensuring there are no audible air leaks is crucial because air leaks can compromise the performance of the braking system. Air is necessary for the proper operation of the brakes, and any loss of air pressure can lead to brake failure, increasing the risk of accidents. Therefore, detecting any leaks during the inspection is a vital step in ensuring the vehicle is safe to operate.

Additionally, ensuring that the glad hands and air lines are secure is also critical. Glad hands are the coupling mechanisms that connect the air supply lines between the tractor and trailer. If these connections are not secure, it could lead to a disconnection while driving or an air pressure loss that can affect braking effectiveness. Inspecting these connections helps prevent potential breakdowns and enhances overall safety.

Together, checking for audible air leaks and securing glad hands and air lines constitute essential parts of the pre-hill inspection, ensuring the vehicle is safe to drive. This makes the option that includes both checks the correct choice, emphasizing the importance of these inspections in maintaining safe operations for vehicles with air brake systems.