13-21. TM 9-2320-209-20-3-2 AIR SYSTEM LINES AND FITTINGS REMOVAL AND REPLACEMENT. NOTE Procedures given are typical and cover all the dif- ferent types of installations that you will find on the trucks. Procedures do not show any one truck system. Refer to system schematic illustra- tions used as support diagrams for troubleshooting each system (vol. 2, chapter 46, fig. 46-2) TOOLS: 5/8-inch combination box and open end box wrench 3/8-inch combination box and open end box wrench 9/16-inch open end wrench (2) 3/4-inch combination box and open end box wrench 11/16-inch combination box and open end box wrench 13/16-inch combination box and open end box wrench Adjustable wrench 7/8-inch combination box and open end box wrench 1/2-inch drive ratchet 9/16-inch socket SUPPLIES: None PERSONNEL: One EQUIPMENT CONDITION: Truck parked, engine off, handbrake set. a. Preliminary Procedure. Vent air system pressure. Refer to para 13-20. 13-149