TM 9-2320-209-20-3-2 13-41. AIR BRAKE HOSE REMOVAL AND REPLACEMENT. TOOLS: 1-inch wrench 11/16-inch wrench 12-inch adjustable 15-inch adjustable SUPPLIES: None PERSONNEL: One wrench wrench EQUIPMENT CONDITION: Truck parked, engine off, handbrake set. a. Preliminary Procedure. Vent air system pressure. Refer to para 13-20. b. Removal. FRAME 1 1. Turn valve handle (1) to the on (down) position. 2. Using adjustable wrench, hold valve (2). Using 1-inch wrench, unscrew coupling nut (3). Take off coupling nut and hose (4). GO TO FRAME 2 13-278