TM 5-4220-225-14
Table 2-3. Daily Predive Procedures (Cont).
Step
Procedure
c.
Locking Device Assembly Inspection.
NOTE
Apply only enough lubricant to coat item concerned
without excess.
(1)
Ensure locking pins are in good condition and operate freely.
Check that detent balls operate properly. Apply a light film of
lubricant to locking pins.
(2)
Inspect locking pins for corrosion, bends or cracks.
(3)
Inspect helmet lugs for corrosion, dents, and loose or damaged
mounting screws.
d.
Exhaust Valve Inspection.
(1)
Check exhaust valve in accordance with applicable procedure
below.
(2)
Lay helmet assembly on its right side with exhaust valve facing
up.
e.
Adjustable Exhaust Valve Check.
NOTE
If handle is loose, tighten friction drag screws until
desired action is achieved.
(1)
Rotate valve handle.Motion should be firm and have some
resistance but operate smoothly through full range, approxi-
mately three turns.
(2)
Depress the chin button with finger pressure. Motion should be
smooth with spring pressure increasing steadily. Upon releasing
finger pressure, valve should shut with spring tension.
f.
Ambient Exhaust Valve Check.
(1)
Remove exhaust valve cover and inspect valve body for dirt,
corrosion, and damage.Inspect diffuser for dirt or damage.
Replace or clean parts as necessary.
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