TM 9-2320-209-10-1 f. Pipeline Contruction Truck Controls and Indicators. 1. Safety brake adjustment screw. Is 3. Drum clutch lever. Is placed right turned right (from under the truck) to make drum ready to turn and left to tighten brake bands which prevent to set drum free. lowering of the load when the clutch 4. Winch drumlock. is set free. . Is pulled out and turned 90° to unlock drum. 2. Drag brake adjustment screw. Is turned right (from under the truck) to increase drag and prevent free spooling. 4-19