What is the main reason for protecting the glad hands when not in use?

The main reason for protecting the glad hands when not in use is to keep the air supply clean, which directly impacts the performance and reliability of the braking system. Glad hands are the connectors that link the air brake system of the tractor to the trailer. If these connectors are left unprotected, contaminants such as dirt, moisture, and debris can enter the air system. This contamination can lead to issues with air quality, resulting in less effective braking and potential problems like frozen or malfunctioning brake components. Ensuring a clean air supply minimizes these risks and helps maintain optimal brake function, which is crucial for safe vehicle operation.