How can a technician check for air leaks in the air brake system?

Answer: B — By listening for hissing sounds and using soapy water on fittings

Using hissing sounds and soapy water on fittings is an effective method for checking for air leaks in the air brake system because it allows the technician to identify the precise location of leaks. When air escapes from fittings, lines, or other components, it often produces a hissing sound, which serves as an auditory indicator of a leak. Applying soapy water creates bubbles at the leak site; if bubbles form, this indicates air is escaping through that particular area. This method is straightforward and helps technicians easily locate leaks without needing to disassemble parts of the braking system. In contrast, while checking with a pressure gauge can provide useful information about system performance, it does not specifically pinpoint the location of leaks. Visual inspections might not reveal all leaks, especially in areas that are hard to see or access. Checking for uneven braking can indicate issues within the brake system, but it does not directly identify air leaks. Thus, using auditory detection and soapy water remains the most effective and practical approach.