TM 9-2320-209-20-3-2 c. Replacement. FRAME 1 1. The air system safety valve (1) is located on trucks in different places, as shown. 2. Using wrench, screw on and tighten air system safety valve (1). NOTE Follow-on Maintenance Action Required: 1. Do air system leak test. Refer to Part 1, para 1-5 2. If spare wheel was taken off, replace it. Refer to TM 9-2320-209-10. END OF TASK 13-182