TM 5-1940-321-13&P
( 11 ) Remove the flat ring-shaped neoprene valve insert gasket (item 4) from the
metal valve insert. See figure 5-6. Clean the gasket by rubbing it between your
thumb and fingers. Stretch the gasket as shown in figure 5-7 while inspecting it
for cuts and cracks. Gaskets in good condition can be reinstalled. If damaged,
a new gasket must be installed.
Figure 5-6. Removing Flat Ring-shaped Neoprene Valve Insert Gasket from Metal Valve Insert.
Figure 5-7. Inspecting Ring-shaped Flat Neoprene Valve Insert Gasket for Cuts and Cracks.