Maintenance - Makita 6905B Instruction Manual

Operation
The proper tightening torque may differ depending upon the kind or size of the bolt. The relation between tightening
torque and tightening time is shown in the figure below.
Hold the tool firmly and place the socket over the bolt or nut. Turn the tool on and tighten for the proper tightening time.
NOTE:
• Hold the tool pointed straight at the bolt or nut without applying excessive pressure on the tool.
• Excessive tightening torque may damage the bolt or nut.
The tightening torque is affected by a wide variety of fac-
tors including the following. After tightening, always
check the torque with a torque wrench.
1. Socket
• Failure to use the correct size socket will cause a
reduction in the tightening torque.
• A worn socket (wear on the hex end or square
end) will cause a reduction in the tightening
torque.
2. Bolt
• Even though the torque coefficient and the class of
bolt are the same, the proper tightening torque will
differ according to the diameter of bolt.
• Even though the diameters of bolts are the same,
the proper tightening torque will differ according to
the torque coefficient, the class of bolt and the bolt
length.
3. The use of the universal joint or the extension bar
somewhat reduces the tightening force of the impact
wrench. Compensate by tightening for a longer
period of time.
4. The manner of holding the tool will affect the torque.
kg•cm
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0 1 2 3 4 5 6
Tightennig time
Rated voltage
90% of rated voltage

MAINTENANCE

CAUTION:
Always be sure that the tool is switched off and
unplugged before carrying out any work on the tool.
Replacement of carbon brushes (Fig. 4 & 5)
Replace carbon brushes when they are worn down to the
limit mark. Both identical carbon brushes should be
replaced at the same time.
To maintain product safety and reliability, repairs, mainte-
nance or adjustment should be carried out by a Makita
Authorized Service Center.
For 6906
For 6905B
seconds
7 8
5