TM 5-4220-225-14
4-17.
Helmet Base Breech Ring.
This task covers
Replace
INITIAL SETUP
Tools
Materials/Parts
5/64-inch, Hex Wrench (Item 17, Appendix B)
RTV Sealant (Item 1, Appendix E)
Wrench, Torque (Item 14, Appendix B)
Halocarbon Grease (Item 10, Appendix E)
MK12 Test Set (Item 44, Appendix B)
Spare Parts Kit
Adapter, Socket Wrench (Item 41, Appendix B)
Helmet Breech Ring
Insert, Hex (Item 51, Appendix B)
Replace. (figure 4-10)
(1)
Remove preformed packing (1).
(2)
Remove 10 screws (2) and remove helmet breech ring (3) and preformed packing (4), which is discarded.
(3)
Lightly lubricate new preformed packing (4).
(4)
Install preformed packing (4) and breech ring (3) and secure with 10 screws (2) finger tight.
(5)
Torque screws (2) to 18-20 in.-lb (1.7-2.3 Nm) using a staggered sequence.
(6)
Lightly lubricate preformed packing (1) and install.
4-28
