Air brakes can lose their effectiveness from a variety of causes. If a slack adjuster isn’t properly set, the pushrod stroke of that brake chamber can increase to the point that you have to press the brake pedal farther down to achieve the same amount of braking force. If brake drums overheat from repeated or continuous application of the brakes, the drums will expand away from the brake shoes, reducing braking effectiveness (brake fade). Moisture and oil can collect in the bottoms of the air tanks, forming a corrosive sludge that can pass from the tank into other components of the air brake system, damaging them. In cold weather, water in the air tanks can freeze, and ice in the lines or valves can block the flow of compressed air.