Maintenance And Inspection - Hitachi WR18DSHL Handling Instructions Manual

3. Holding the tool
Hold the impact wrench fi rmly with both hands. In this
case hold the wrench in line with the bolt.
It is not necessary to push the wrench very hard. Hold
the wrench with a force just suffi cient to counteract the
impact force.
4. Confi rm the tightening torque
The following factors contribute to a reduction of the
tightening torque. So confi rm the actual tightening torque
needed by screwing up some bolts before the job with
a hand torque wrench. Factors aff ecting the tightening
torque are as follows.
(1) Voltage
When the discharge margin is reached, voltage
decreases and tightening torque is lowered.
(2) Operating time
The tightening torque increases when the operating time
increases. But the tightening torque does not increase
above a certain value even if the tool is driven for a long
time.
(3) Diameter of bolt
The tightening torque diff ers with the diameter of the bolt.
Generally a larger diameter bolt requires larger tightening
torque.
(4) Tightening conditions
The tightening torque diff ers according to the torque ratio;
class, and length of bolts even when bolts with the same
size threads are used. The tightening torque also diff ers
according to the condition of the surface of workpiece
through which the bolts are to be tightened. When the
bolt and nut turn together, torque is greatly reduced.
(5) Using optional parts
The tightening torque is reduced a little when an
extension bar, universal joint or a long socket is used.
(6) Clearance of the socket
A worn or deformed hex. or a square-holed socket will
not give an adequate tightness to the fi tting between the
nut or anvil, consequently resulting in loss of tightening
torque.
Using an improper socket which does not match to the
bolt will result in an insuffi cient tightening torque.
(7) Tightening torque varies, depending on the battery's
charge level.

MAINTENANCE AND INSPECTION

1. Inspecting the socket
A worn or deformed hex. or a square-holed socket will
not give an adequate tightness to the fi tting between
the nut or anvil, consequently resulting in loss of
tightening torque. Pay attention to wear of a socket holes
periodically, and replace with a new one if needed.
2. Inspecting the mounting screws
Regularly inspect all mounting screws and ensure that
they are properly tightened. Should any of the screws be
loose, retighten them immediately. Failure to do so may
result in serious hazard.
3. Maintenance of the motor
The motor unit winding is the very "heart" of the power
tool.
Exercise due care to ensure the winding does not
become damaged and/or wet with oil or water.
4. Inspecting the carbon brushes (Fig. 9)
The motor employs carbon brushes which are
consumable parts. Since and excessively worn carbon
brush can result in motor trouble, replace the carbon
brush with new ones when it becomes worn to or near
the "wear limit". In addition, always keep carbon brushes
clean and ensure that they slide freely within the brush
holders.
NOTE:
When replacing the carbon brush with a new one, be sure
to use the Hitachi Carbon Brush Code No. 328481.
5. Replacing carbon brushes
Take out the carbon brush by fi rst removing the brush
cap and then hooking the protrusion of the carbon brush
with a fl at head screw driver, etc., as shown in Fig. 11.
When installing the carbon brush, choose the direction
so that the nail of the carbon brush agrees with the
contact portion outside the brush tube. Then push it in
with a fi nger as illustrated in Fig. 12. Lastly, install the
brush cap.
CAUTION:
Be absolutely sure to insert the nail of the carbon brush
into the contact portion outside the brush tube. (You can
insert whichever one of the two nails provided).
Caution must be exercised since any error in this
operation can result in the deformed nail of the carbon
brush and may cause motor trouble at an early stage.
6. Cleaning of the outside
When the impact wrench is stained, wipe with a soft dry
cloth or a cloth moistened with soapy water. Do not use
chloric solvents, gasoline or paint thinner, as they melt
plastics.
7. Storage
Store the impact wrench in a place in which the
temperature is less than 40°C, and out of reach of children.
NOTE:
Make sure that the battery is fully charged when stored
for a long period (3 months or more). The battery with
smaller capacity may not be able to be charged when
used, if stored for a long period.
8. Service parts list
A: Item No.
B: Code No.
C: No. Used
D: Remarks
CAUTION
Repair, modifi cation and inspection of Hitachi Power
Tools must be carried out by an Hitachi Authorized
Service Center.
This Parts List will be helpful if presented with the tool to
the Hitachi Authorized Service Center when requesting
repair or other maintenance.
In the operation and maintenance of power tools, the
safety regulations and standards prescribed in each
country must be observed.
MODIFICATIONS
Hitachi Power Tools are constantly being improved
and modifi ed to incorporate the latest technological
advancements.
Accordingly, some parts (i.e. code numbers and/or
design) may be changed without prior notice.
Important notice on the batteries for the Hitachi
cordless power tools
Please always use one of our designated genuine
batteries. We cannot guarantee the safety and
performance of our cordless power tool when used with
batteries other than these designated by us, or when
the battery is disassembled and modifi ed (such as
disassembly and replacement of cells or other internal
parts).
NOTE
Due to HITACHI's continuing program of research and
development, the specifi cations herein are subject to
change without prior notice.
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