Hitachi N 5008AC Technical And Service Manual page 19

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 [13] does not return.
A
Swollen Cylinder O-ring (D) [11] (Use of
Exhaust vent
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]
B Loose Hex. Socket Hd. Bolt M5 x 20 [1]
Broken Gasket (B) [4]
Exhaust cover
Damaged seal surfaces of Body [20] and
Exhaust Cover [3]
C
Nose
Damaged Cylinder O-ring (B) [18] or O-ring
D
of Cylinder Guide [17] (worn, deformed or
Nose
broken)
Defective Body [20] (worn, corroded or
deformed)
Defective Urethane Ball (C) D7.14 [47]
E
(damaged or deformed)
Trigger valve
Defective ball sheet surface of Trigger Valve
Bushing [49] (damaged, deformed or worn)
Defective Valve Packing [46] (damaged,
deformed or broken)
Soiled or damaged valve packing sheet
surface of Body [20]
Incursion of foreign materials
Defective Gaskets (B) (C) [4] [5] (damaged or
F
yielded)
Safety valve
Discorded air vent of Gasket (B) [4]
Defective O-ring (S-65) [10] or Cylinder
O-ring (D) [11] of the Cylinder Plate [12]
(worn, deformed or broken)
Defective Cylinder O-ring (D) [11] (worn,
deformed or broken)
Loose Hex. Socket Hd. Bolt M5 x 16 [35]
G
Broken Gasket (D) [33]
Cap
Defective seal surface of the Body [20] or
Cap [34]
).
). (See Parts List and exploded assembly diagram for part
Cause
When trigger valve/
safety valve are ON
Defective Exhaust Valve
[6] (worn, deformed, or
broken)
Deformed Nose [25]
Loose Nylock Hex. Socket
Hd. Bolt M5 x 16 [26]
Broken or cracked
Piston Bumper [22]
Deformed Piston [9]
Deformed Nose [25]
Air will leak slightly from
the lower portion due to
construction.
--- 16 ---
When trigger valve ON/
safety valve OFF
Defective Plunger O-ring
[42] (worn, deformed or
broken)
Defective outside
O-ring (S-12) [43] of
Trigger Valve Bushing
[49]
Defective outside O-ring
(S-12) [43] of the Valve
Bushing [44] (worn,
deformed or broken)
Defective Plunger O-ring
[42] (worn, deformed or
broken)
Defective Plunger Spring
[40] (deformed or broken)
Defective safety Valve
Bushing [44] (deflected,
deformed or broken)