Remove and Replace the CO2 Overpressure Valve and Valve Base.

TM 5-1940-321-13&P

( 7 ) Install the new valve base and large neoprene valve base gasket though the

incision. Install the valve base metal compression washer and valve base nut.

Tighten the valve base nut moderately while holding the valve base through the

incision. Use a collar nut spanner.

( 8 ) Apply an inner patch to the incision using a hypalon neoprene fabric and neoprene

glue. Refer to Appendix F.

( 9 ) Wait 12 hours for the glue to develop sufficient bond strength; then inflate the craft

to 180 mbar. (2.6 psi). Check for leaks at the inner patch and the valve using the

( 10 ) If no leaks are observed, apply an outer patch over the inner patch as described in

( 11 ) Wait 48 hours before inflating the craft to 240 mbar (3.5 psi).

( 12 ) Check for leaks around the CO2 inlet valve using the air leak test (paragraph 6-3).

j. Remove and Replace the CO2 Overpressure Valve and Valve Base. This corrective

maintenance procedure is performed by direct support personnel. The CO2 overpressure valves must be

removed and replaced when they fail to seat or otherwise leak. CO2 overpressure valves are not

repairable and must be replaced when they fail to function properly. CO2 overpressure valve bases must

also be removed and replaced to correct air leaks between the valve and the buoyancy tube fabric that

cannot be corrected by tightening the overpressure valve. Before removing and replacing the molded

valve base, which is glued inside the buoyancy tube, verify that the leak cannot be corrected by servicing

the valve. Refer to figure 7-25 for CO2 overpressure valve components. Perform the air leak test (chapter

6, paragraph 6-3) to determine the exact point at which the CO2 overpressure valve is leaking. Most leaks

can be corrected by replacing the plastic CO2 overpressure valve. The valve must be tight. Use the plastic

socket wrench to tighten. Do not insert a handle into the square drive hole in the plastic socket. Tighten

the valve by using your hand on the plastic socket wrench. See figure 7-26. If the leak cannot be

corrected as described above, and the leak test (paragraph 6-3) indicates the leak is at the hold in the

fabric, or the female internal threads in the valve base are damaged, remove and replace the neoprene

valve insert base. Referring to figure 7-27, remove and replace the CO2 overpressure neoprene valve

insert base using the following procedure:

7-36