Hitachi NR 65AK Service Manual page 22

Problem
(
< Output section:piston, driver
3) Nails cannot
blade, etc. >
be driven into
Air pressure is too low.
the workpiece
completely:
the heads
cannot be
O-ring in the piston is
made flush.
abnormal (worn or damaged).
(continued)
Piston bumper is abnormal.
O-ring in the cylinder is
abnormal (removed, deformed
or damaged).
Driver blade is abnormal
(deformed, burrs or damaged).
Cylinder inside surface is
abnormal (packed with dust,
or worn).
Head valve sliding surface
is abnormal (seized or
damaged, or lubrication is
needed).
Head valve spring is
abnormal (fatigued or
damaged).
<Control valve section>
Plunger (A), valve piston
(B), valve bushing (A) or
valve bushing (B) is
abnormal (seized or
damaged).
O-ring or sliding surface is
worn or needs lubrication.
<Nails>
4) Nails jam.
Unspecified nails are used.
Abnormal nails are mixed.
Nail heads are too large or
too small.
Collating paper are
abnormal (broken, welding
failed, deformed or welding
position failed).
Collating paper are
deformed (deformed in
collation angle or collation
pitch).
Possible cause
: Most-common cause)
Inspection method
Pull the nail feeder
backward and perform idle
drivng to check that the
driver blade is returned.
Check that nails can be
driven at 5.4 bar
(5.5 kgf/cm 2 , 80 psi).
Perform idle driving to check
the driving operation.
Perform idle driving to check
that the driver blade is not
held in the down position.
Disassemble the control
valve section and check
the O-rings.
Check if the specified nails
are used.
Check the nails as follows.
36˚
--- 18 ---
Remedy
Adjust the air pressure to
5.4 - -- 8.3 bar
2
(5.5 --- 8.5 kgf/cm , 80 ---120 psi).
Replace the O-ring.
Replace the piston bumper.
Reassemble or replace the
parts.
Correct or replace the part.
Remove dust and then
lubricate.
Replace the part.
Replace the part.
Apply grease.
Replace the part.
Replace the defective part.
Replace the abnormal part.
Apply grease.
Use specified nails.
Remove the abnormal nails
and load the nailer with
proper nails.
UNIT: mm (inch)
Type d L
38
3.3
A
(0.315)
(1-1/2)
(0.131)
3.8 38
B
(0.315)
(0.148) (1-1/2)
3.8 64
C
(1.315)
(0.148) (2-1/2)
4.1 64
D
(0.162) (2-1/2)
(1.315)
l
8
8
33.4
33.4