Commercial Driver’s License (CDL) Practice Exam

Moisture in the air system is a common cause of ice forming in air brake valves because compressed air contains moisture, and when the air is cooled, this moisture can condense and freeze. In cold weather, the temperatures in the air brake system can drop significantly, leading to the condensation of water vapor within the air lines and brake valves. Once this moisture freezes, it can obstruct the proper functioning of the air brake system, leading to potential brake failure or reduced effectiveness. Maintaining a dry air system is critical in preventing ice formation; this is typically done through the use of dryers that can remove moisture before it enters the brake system. Understanding the importance of moisture control is essential for maintaining the reliability and safety of an air brake system, especially in colder climates where the risk of freezing is heightened.