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Defective Exhaust Valve
[6] (worn, deformed or
broken)
Cylinder [13] does not return.
Swollen Cylinder O-rings (D) [11] or (A) [16]
or (B) [18] (Use of unsuitable oil causes swelling.
Advise the customer to use Shell Tonna Oil T32.)
Deformed Cylinder [13] or Cylinder Guide [17].
Yielded or broken Cylinder Spring [15].
Defective Head Cap [7] (worn rubber portion
or broken)
Broken Gaskets (C) [5]
Loose Hex. Socket Hd. Bolt M5 x 20 [1]
Broken Exhaust Cover [3]
Loose Hex. Socket Hd. Bolt M5 x 20 [5]
Broken Gasket (B) [4]
Damaged seal surfaces of Body Ass'y [19]
and Exhaust Cover [3]
Damaged Cylinder O-ring (B) [18] or O-ring
of Cylinder Guide [17] (worn, deformed or
broken)
Defective Body Ass'y [19] (worn, corroded or
deformed)
Defective Urethane Ball (C) D7.14 [54]
(damaged or deformed)
Defective ball sheet surface of Trigger Valve
Bushing [57] (damaged, deformed or worn)
Defective Valve Packing [53] (damaged,
deformed or broken)
Soiled or damaged valve packing sheet
surface of Body Ass'y [19]
Incursion of foreign materials
Defective Gaskets (B) [4] or (C) [5]
(damaged or yielded)
Discorded air vent of Gasket (B)
Defective O-ring [10] or Cylinder O-ring (D)
[11] of the Cylinder Plate [12] (worn,
deformed or broken)
Defective Cylinder O-ring (A) [16] or (B) [18]
(worn, deformed or broken)
Exhaust vent
Air leak part
Cause
When trigger valve/safety valve are OFF
When trigger valve/
safety valve are ON
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 ( ). (See Parts List and exploded assembly diagram for part
name and location.)
Deformed Nose Ass'y [22]
Loose Nylock Hex. Socket
Hd. Bolt M5 x 16 [24]
When trigger valve ON/
safety valve OFF
A
Exhaust cover
B
Nose
C
Guide Plate
D
Trigger valve
E
Safety valve
F
Cap
G
Air will leak slightly from
the lower portion due to
construction.
Defective Plunger O-ring
[43] (worn, deformed or
broken)
Defective outside
O-ring [55] of Trigger
Valve Bushing [57]
(When contact actuation
is selected)
Broken or cracked
Piston Bumper [21]
Deformed Piston [9]
Deformed Nose Ass'y
[22]
Scratched or damaged
O-ring [44] outside the
Valve Bushing [45] and
the Plunger O-ring [49]
inside the Valve Bushing
[45]
Defective Plunger O-ring
[43] (worn, deformed or
broken)
Defective Plunger Spring
[41] (deformed or broken)
Defective Valve Bushing
[45] (deflected, deformed
or broken)
Scratched or damaged
O-ring [46] inside the Valve
Sleeve [47] (When single
actuation is selected)
Scratched or damaged
O-ring [44] outside the
Valve Bushing [45] at
the safety valve portion
(When single actuation
is selected)
Loose Hex. Socket Hd. Bolt M5 x 16 [36]
Broken Gasket (D) [34]
Defective seal surface of the Body Ass'y [19]
or Cap [35]
Summary of Contents for NT 65A3
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