This Service Bulletin addresses the issue of excessive moisture in the air system for various Freightliner truck models, including the FLA COE, FLB COE, FLD Conventional, Business Class, FLC 112 Conventional, Century Class Conventional, Argosy COE, Cargo, Columbia, Coronado, Business Class M2, and Cascadia. It covers specific models like the 108SD/114SD and provides guidance on diagnosing and resolving the problem of excess moisture within the air braking system. This bulletin outlines the potential causes of moisture accumulation, describes the necessary inspection and repair procedures, and provides recommendations for preventative maintenance to mitigate future occurrences. The information contained within this Service Bulletin is essential for technicians and mechanics who service these Freightliner truck models, as it equips them with the knowledge and steps to ensure the safe and efficient operation of the vehicle's air braking system.

## Excessive Moisture in the Air System - A Common Issue Affecting Freightliner Trucks Excessive moisture in the air system is a recurring problem affecting various Freightliner truck models, from the classic FLC 112 Conventional to the modern Cascadia. This issue can manifest in various forms, including water in the air tanks, condensation in the air lines, and even frozen air lines in cold weather. The presence of moisture can lead to several detrimental consequences for truck owners and operators. Primarily, it can significantly impact braking performance, leading to reduced braking efficiency and potentially dangerous situations. Furthermore, moisture can cause corrosion in air lines and components, leading to costly repairs and potential system failure. Additionally, it can hinder the efficient operation of other air-powered systems like suspension and shifting mechanisms, impacting the overall vehicle performance. The root cause of this problem can be attributed to several factors. One common cause is inadequate air dryer performance, failing to remove sufficient moisture from the compressed air. Environmental conditions, particularly high humidity, can also contribute to moisture buildup in the air system. Another factor is the lack of regular maintenance, including air tank drainage and air dryer filter replacement. Furthermore, certain design features in older models, such as poorly-sealed air lines or inadequate venting systems, can also contribute to the issue. Solving this problem requires a multi-pronged approach. It's crucial to ensure the air dryer is functioning correctly and is appropriately sized for the vehicle's needs. Regular maintenance, including regular draining of air tanks and timely filter replacement, is paramount. Additionally, using high-quality compressed air and addressing any design flaws that contribute to moisture accumulation can prevent future issues. Addressing excess moisture can significantly improve vehicle performance and safety, minimize repair costs, and prolong the lifespan of your Freightliner truck.