Hitachi NR 83A2 Technical Data And Service Manual page 29

Inspection priorities:
In the table below, possible causes of air leakage and their repair procedures are marked in accordance with the
likelihood of possible failure.
(1) First priority items are marked with an asterisk ( ).
(2) Second priority items (seal portions) are marked with a double circle (
(3) Remaining items are marked with a single circle (
name and location.)
Air leak part
When trigger valve/safety valve are OFF
Cylinder [17] does not return.
A
Swollen Cylinder O-ring [16] (Use of
Exhaust vent
unsuitable oil causes swelling. Advise the
customer to use Shell Tonna Oil T32.)
Deformed Cylinder [17] or Cylinder Guide [22].
Yielded or broken Cylinder Spring [20].
Defective Head Cap and Gasket Set [10]
(worn rubber portion or broken)
Broken Gaskets (C) (F) [8] [6]
Loose Hex. Socket Hd. Bolt (W/Flange)
M6 x 45 [1]
Broken Exhaust Cover [4]
B Loose Hex. Socket Hd. Bolt (W/Sp. Washer)
M6 x 25 [3]
Exhaust cover
Broken Gasket (B) [5]
Damaged seal surfaces of Body Ass'y [25]
and Exhaust Cover [4]
C
Nose
Damaged Cylinder O-ring [18] or O-ring of
D
Cylinder Guide [22] (worn, deformed or
Nose
broken)
Defective Body Ass'y [25] (worn, corroded or
deformed)
Defective Urethane Ball (C) D7.14 [62]
E
(damaged or deformed)
Trigger valve
Defective ball sheet surface of Trigger Valve
Bushing [65] (damaged, deformed or worn)
Defective Valve Packing [61] (damaged,
deformed or broken)
Soiled or damaged valve packing sheet
surface of Body Ass'y [25]
Incursion of foreign materials
F
Defective Gaskets (C) (F) [8] [6] (damaged
or yielded)
Safety valve
Deformed or broken Gasket (G) [23]
Defective O-ring [13] or Cylinder O-ring [14]
of the Cylinder Plate [15] (worn, deformed or
broken)
Defective Cylinder O-ring [16] (worn,
deformed or broken)
).
). (See Parts List and exploded assembly diagram for part
Cause
When trigger valve/
safety valve are ON
Defective Exhaust Valve
[9] (worn, deformed, or
broken)
Deformed Nose [32]
Loose Nylock Hex. Socket
Hd. Bolt M8 x 22 [33]
Damaged Gasket (A) [28]
Broken or cracked
Piston Bumper (B) [27]
Deformed Piston [12]
Deformed Nose [32]
Air will leak slightly from
the lower portion due to
construction.
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When trigger valve ON/
safety valve OFF
Improperly mounted or
damaged Gasket (G) [23]
Scratched or damaged
O-ring [58] outside the
Valve Bushing [57] at the
safety valve portion
(When single actuation is
selected)
Defective Plunger O-ring
[67] (worn, deformed or
broken)
Defective outside
O-ring [58] of trigger
Valve Bushing [57]
(When contact actuation
is selected)
Scratched or damaged
O-ring [58] outside the
Valve Bushing [57] and
the Plunger O-ring [71]
inside the Valve Bushing
[57]
Valve Bushing [57]
Defective plunger O-ring
[67] (worn, deformed or
broken)
Defective Plunger Spring
[54] (deformed or broken)
Defective Valve Bushing
[57] (deflected, deformed
or broken)