Hitachi NT 65M2 Technical Data And Service Manual page 21

Air leakage point
(C) Blade guide
(D) Air outlet, valve
bushing
(E) Control valve (1)
(F) Control valve (2)
(G) Gap (A)
When control valve OFF
The Cylinder O-ring (I.D 59.6) [15] is abnormal
(broken or damaged).
The seal surface of the Body Ass'y [31] is
abnormal ( c portion).
The Valve Packing [20] is damaged.
The O-ring (1AP-3) [24] of the Plunger [22] is
abnormal (worn, broken or damaged).
The O-ring (S3) [23] of the Plunger [22] is
abnormal (worn, broken or damaged).
The screw of the Valve Bushing [26] is loose.
The O-ring (1AP-10) [64] of the Valve Piston
[63] is abnormal (worn, broken or flawed).
The lower O-ring (P-7) [62] of the Valve Piston
[63] is abnormal (worn, broken or flawed).
The O-ring (P-18) [61] of Valve Bushing (B)
[60] is abnormal (broken or flawed).
The internal surface g of the valve cavity of
the Body Ass'y [31] is abnormal.
The O-ring (I.D 1.8) [66] of the Plunger [67] is
abnormal (worn, broken or flawed).
Valve Bushing (A) [68] is abnormal (sliding
surface of the Plunger [67] is deformed or
flawed).
Gasket (B) [46] is damaged.
The Hex. Socket Hd. Bolt M5 x 16 [49] is loose.
The seal surface of the Body Ass'y [31] is abnormal (broken, deformed or scratched).
Possible cause
The Piston Bumper [18] is abnormal ( d or e
portion is damaged, deformed or cracked).
The Piston [12] is abnormal (driver blade or
sealed face is deformed).
The e surface of the Body Ass'y [31] is
deformed.
The upper O-ring (P-7) [62] of the Valve Piston
[63] is abnormal (worn, broken or flawed).
The Feed Piston O-ring (I.D. 14) [59] of Valve
Bushing (B) [60] is abnormal (broken or
flawed).
The internal surface f of the valve cavity of the
Body Ass'y [31] is abnormal.
The upper O-ring (I.D 1.8) [66] of the Plunger
[67] is abnormal (worn, broken or flawed).
The Valve Piston [63] is abnormal (sliding
surface of the Plunger [67] is deformed or
flawed).
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When control valve ON