TM 5-4220-226-1 4&P
c. Installation
(1) Apply silicone sealant to helmet shell over the side block mounting screw and side block stud
openings.
(2) Insert side block stud (7) through helmet shell. Install washer (6), lockwasher (5), and nut (4). Install
side block screw (8).
(3) Thread bent tube (1) with new preformed packing (3) onto inlet cap of demand regulator. Do not
tighten.
(4) With new washer (2) installed in opposite bent tube nut, thread nut onto side block. Tighten nut onto
side block and then tighten opposite nut onto demand regulator.
4-14. One-Way Valve Assembly Maintenance.
This task covers:
a.
Removal
b.
Installation
INITIAL SETUP
Tools
Materials Required (continued)
Tool Kit, General Mechanic's (item 4, appx B)
Nonionic Detergent (NID) Solution (item 3, appx E)
Silicone Lubricant (item 8, appx E)
Materials Required
Preformed Packing
Soft Bristle Brush (item 1, appx E)
Equipment Conditions
Clean, Lint-Free Cloths (item 2, appx E)
Warm Fresh Water (item 4, appx E)
Helmet adapter hose removed (para 4-26).
a. Removal
(1) Place helmet on clean workbench.
(2) Remove one-way valve (1) from side block (2).
(3) Remove and discard preformed packing (3).
4-11
