(6) Fasten assembled yoke to neck clamp with hinge sleeve (2) and two hinge bolts (1).
f. Neck Clamp Adjustment
(1) Place the assembled neck dam and yoke assembly on the helmet.
(2) Place the neck clamp lever in the locked (or closed) position. If it will not close, loosen the
adjustment locknut (16) until it does.
(3) Loosen nut (19) by turning it so that it travels toward the lever. Tighten locknut (16) until some
tension is present. At this point, test the lever action. You should be able to pull the lever open about
an inch and have it snap closed. The lever should open without excessive force if pulled out several
(4) Test by opening and closing the lever several times. When the adjustment is correct, tighten nut (19)
against lockwasher (18). If a new neck dam was installed, readjustment may be necessary after a
few days due to compression of the neck dam rubber.
4-13. Side Block Assembly Maintenance.
This task covers:
Cleaning and Inspection
Materials Required (continued)
Tool Kit, General Mechanic's (item 4, appx B)
Lacquer Thinner (item 5, appx E)
Silicone Sealant (RTV) (item 9, appx E)
Soft Bristle Brush (item 1, appx E)
Clean, Lint-Free Cloths (item 2, appx E)
Warm Fresh Water (item 4, appx E)
Nonionic Detergent (NID) Solution (item 3, appx E)
Muffler air train removed (para 4-19).
(1) Place helmet on clean workbench.
(2) Unthread bent tube assembly (1) from side block.
(3) Holding inlet cap on the demand regulator, loosen the opposite end of the bent tube assembly.
Unthread the nut until it becomes free, then pull the bent tube assembly straight away from the
demand regulator. Remove washer (2) and preformed packing (3). Discard washer and packing.
(4) On inside of helmet, remove nut (4), lockwasher (5), and washer (6) from stud (7). Remove side
block screw (8).
(5) Remove side block assembly (9) from side of helmet.