What should you do if you hear a hissing sound from the air brake system?

Hearing a hissing sound from the air brake system is a sign that there may be a leak in the system. This sound typically indicates that air is escaping, which can affect the performance and safety of the braking system. A leak can lead to a gradual loss of air pressure, potentially resulting in brake failure, which is dangerous while operating a vehicle.

To ensure safety and proper function, it is essential to check for leaks if you notice such sounds. This typically involves inspecting various components of the air brake system, including hoses, fittings, and the brake chambers, to identify the source of the leak. Addressing this issue promptly helps maintain the integrity of the braking system, thereby ensuring that the vehicle can stop effectively when needed.

Ignoring the hissing sound or assuming it's normal can lead to serious safety hazards. Increasing speed or reducing air pressure in response to a leak would further compromise the braking system, making it imperative to take the correct action of checking for leaks.