TM 9-2320-209-20-3-2 c. Replacement. (1) Left side air tank. FRAME 1 1. 2. 3. 4. GO Using 11/16-inch wrench, screw in and tighten drain cock (1). Using 7/8-inch wrench, screw in and tighten tee fitting (2). Using 3/4-inch wrench, screw in and tighten elbow fitting (3) to positions noted. Using 3/4-inch wrench, screw on and tighten safety valve (4). Using 3/4-inch wrench, screw in and tighten tee fitting (5) to position noted. TO FRAME 2 13-223