How can you check the slack adjusters?

Checking slack adjusters is crucial for ensuring the proper functioning of a vehicle's braking system. The correct method involves physically assessing the slack adjusters to determine if they are functioning correctly, which is done by pulling hard on each adjuster. This action allows the driver or mechanic to verify if they are properly adjusted within the specified limits and to ensure that they move freely without excessive play or resistance. Properly adjusted slack adjusters contribute to the efficiency and safety of the braking system, which is vital for the operation of commercial vehicles.

The other options do not provide a reliable method for checking slack adjusters. Observing their color does not indicate their functionality, as they may be discolored for various reasons unrelated to their performance. Listening for a click sound is not a definitive test and may lead to misinterpretation of the condition of the adjusters, while measuring their temperature does not correlate with their operational status. Effective maintenance of slack adjusters is critical for safety, and physically checking them through a pull test is the best practice.