Maintenance - Makita 6918FD Instruction Manual

Operation (Fig. 6 & 7)
The proper fastening torque may differ depending upon
the kind or size of the bolt. The relation between fasten-
ing torque and fastening time is shown in the figures.
Hold the tool firmly and place the socket over the bolt or
nut. Turn the tool on and fasten for the proper fastening
time.
NOTE:
• Hold the tool pointed straight at the bolt or nut without
applying excessive pressure on the tool.
• Excessive fastening torque may damage the bolt or
nut. Before starting your job, always perform a test
operation to verify the adequate fastening speed and
time for your bolt or nut.
The fastening torque is affected by a wide variety of fac-
tors including the following. After fastening, always check
the torque with a torque wrench.
1. When the battery cartridge is discharged almost
completely, voltage will drop and the fastening
torque will be reduced.
2. Socket
• Failure to use the correct size socket will cause a
reduction in the fastening torque.
• A worn socket (wear on the hex end or square
end) will cause a reduction in the fastening torque.
3. Bolt
• Even though the torque coefficient and the class of
bolt are the same, the proper fastening torque will
differ according to the diameter of the bolt.
• Even though the diameters of bolts are the same,
the proper fastening torque will differ according to
the torque coefficient, the class of bolt and the bolt
length.
4. The use of the universal joint or the extension bar
somewhat reduces the fastening force of the impact
wrench. Compensate by fastening for a longer
period of time.
5. Type of materials to be fastened, the manner of
holding the tool and the tool speed will affect the
torque.
CAUTION:
If the tool is operated continuously until the battery car-
tridge has discharged, allow the tool to rest for 15 min-
utes before proceeding with a fresh battery.

MAINTENANCE

CAUTION:
Always be sure that the tool is switched off and the bat-
tery cartridge is removed before carrying out any work on
the tool.
Replacement of carbon brushes (Fig. 8 & 9)
Remove and check the carbon brushes regularly.
Replace when they wear down to the limit mark. Keep
the carbon brushes clean and free to slip in the holders.
Both carbon brushes should be replaced at the same
time. Use only identical carbon brushes.
Use a screwdriver to remove the brush holder caps. Take
out the worn carbon brushes, insert the new ones and
secure the brush holder caps.
After replacing brushes, insert the battery cartridge into
the tool and break in brushes by running tool with no load
for about 1 minute. Then check the tool while running and
electric brake operation when releasing the switch trig-
ger. If electric brake is not working well, ask your local
Makita service center for repair.
To maintain product SAFETY and RELIABILITY, repairs,
any other maintenance or adjustment should be per-
formed by Makita Authorized Service Centers, always
using Makita replacement parts.
ACCESSORIES
CAUTION:
• These accessories or attachments are recommended
for use with your Makita tool specified in this manual.
The use of any other accessories or attachments might
present a risk of injury to persons. Only use accessory
or attachment for its stated purpose.
If you need any assistance for more details regarding
these accessories, ask your local Makita service center.
• Sockets
• Extension bar
• Universal joint
• Bit adapter
• Screw bits
• Various type of Makita genuine batteries and chargers
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