Maintenance - Makita 6991D Instruction Manual

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
cartridge has discharged, allow the tool to rest for 15
minutes before proceeding with a fresh battery.
Installing set plate (Optional accessory)
(Fig. 9)
Always install the set plate when using battery car-
tridges 9100, 9102 or 9102A. Install the set plate on
the tool with the screw provided.
8

MAINTENANCE

CAUTION:
Always be sure that the tool is switched off and the
battery cartridge is removed before carrying out any
work on the tool.
Replacement of carbon brushes (Fig. 10 & 11)
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,
maintenance or adjustment should be carried out by a
Makita Authorized Service Center.