TM 9-2320-209-20-3-2 (3) Fittings. (a) Tube and elbow assembly CAUTION Fittings are made of soft brass. They can be stripped very easily if tightened too much. Tighten fittings just enough to stop fluid from leaking. NOTE Tube and elbow assembly on air hydraulic cy- linder is used for this typical procedure. FRAME 1 1. Using 3/4-inch open end wrench, screw in and tighten elbow (1). 2. Using 3/4-inch open end wrench, hold elbow (1). Using 13/16-inch combination box and open end box wrench, screw on and tighten tube nut (2). GO TO FRAME 2 13-102