Hitachi NV 50AG2, Technical Data And Service Manual

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Control valve section
Loose Hex. Socket Hd. Bolt M5 x 35
[2]
Damaged Gasket (A) [5]
Abnormal sealed surfaces of Body
Ass'y
[20] , Exhaust Cover [4] or
Cylinder [16]
8-2. Possible Causes and Corrections for Air Leakage
Air leakage repairing positions
Inspection priorities
(1) First, check the items that are marked with
an asterisk (*) in the table below.
(2) Next, check the items that are marked with a
double circule ( ) for any wear and/or
damage.
(3) Finally, check the remaining items (for part
names and circled numbers, refer to the
Parts List).
Section A-A
Air leakage portion
A Exhaust port
Cause
When the trigger is turned off When the trigger is turned on
Abnormal Head Valve (A) [8] and
Cylinder [16] (seal surface b worn or
deformed)
Abnormal Head Valve O-ring
[7]
(Head Valve O-ring [7] or Head Valve
(A) [8] worn, deformed or broken)
Abnormal Exhaust Cover [4]
(damaged)
Abnormal Head Valve (A) [8]
(section a worn, deformed or
broken)
* Abnormal inner surface (section a
deformed or clogged with dirt)
B Exhaust cover
C Nose 1
(Feed piston air passage
portion)
Loose Hex. Socket Hd. Bolt M6 x 20
[31]
Scratched or broken O-ring (1AP-3)
[24]
Abnormal sealed surfaces of Body
Ass'y
[20] or Nose [69]