Chatt-State CDL Class A Pre-Trip Inspection Practice Exam 2026 - Free CDL Pre-Trip Inspection Practice Questions and Study Guide

The correct method for checking the air pressure in the brake system is to use a pressure gauge to ensure it meets the manufacturer specifications. This approach provides a precise measurement of the air pressure, which is crucial for the proper functioning of the braking system. Each vehicle has specific air pressure requirements that need to be met to ensure safety and performance.

Using a pressure gauge allows you to confirm that the air pressure is within safe operating limits, which is vital for effective brake operation. If the pressure is too low, the brakes may not engage properly, leading to potentially dangerous situations. Conversely, if the pressure is too high, it might indicate a malfunction in the system that could also result in brake failure.

Other methods, such as visually checking the air hoses for leaks or listening for the sound of the compressor, may provide preliminary insights but do not offer a definitive assessment of air pressure levels. Pressing the brake pedal can indicate whether brakes are functioning, but it won't provide an accurate measurement of the air pressure in the brake system itself. Therefore, using a pressure gauge is the most reliable and accurate method for ensuring that the brake system is functioning correctly.