Air Brake Practice Test

What exactly is a supply pressure gauge meant for?

1. To check tank pressure

2. To activate the low-pressure alarm

3. To check tire pressure

4. To check for leaks

The correct answer is: To check tank pressure

The supply pressure gauge is designed specifically to measure the pressure of the air in the storage tanks of the air brake system. This gauge provides critical information regarding the amount of compressed air available for the operation of the brakes. Maintaining an adequate air supply is essential for ensuring that the braking system functions properly and safely. Checking tank pressure is vital, as it allows the driver to monitor the system and confirm that there is enough air pressure to engage the brakes effectively. A reading that is too low may indicate a problem with the air supply, which could lead to brake failure or inadequate braking performance, putting safety at risk. In contrast, the other functions listed do not accurately describe the primary role of the supply pressure gauge. While the air system includes components that activate alarms or check for leaks, these tasks are handled by different gauges or safety features within the air brake system. The supply pressure gauge’s sole focus on tank pressure is what sets it apart in terms of function and importance.