John Deere ET-3301-J - Manual (Page 15)

4 1/4-Inch Disc Grinder Operator's Manual 15
Maintenance and Inspection
WARNING: BE SURE TO SWITCH POWER OFF AND DISCONNECT THE
PLUG FROM THE RECEPTACLE DURING MAINTENANCE AND
INSPECTION.
1. Replacing the depressed center wheel:
Replace the depressed center wheel when it has been worn out to about 2-3/8"
(60mm) in external diameter. Confirm that there is no crack or any damage to the
depressed center wheel. If there is a crack or a transformation in the wheel, replace
it immediately.
2. Inspecting the mounting screws:
Regularly inspect all mounting screws and ensure that they are properly tightened.
Should any of the screws be loosened, retighten them immediately.
WARNING: USING THIS GRINDER WITH LOOSE SCREWS IS EXTREMELY
DANGEROUS.
3. Confirm that there is no damage in the wheel
guard, the cord and the housing, etc.
Furthermore, confirm that there is no abnormality
in the activation of the switch.
4. Inspecting the carbon brushes (Fig. 4):
The motor employs carbon brushes which are
consumable parts. Replace the carbon brush
with a new one when it becomes worn to its
wear limit. Always keep carbon brushes clean
and ensure that they slide freely within the
brush holders.
CAUTION: USING THIS GRINDER WITH A CARBON BRUSH WHICH IS
WORN IN EXCESS OF THE WEAR LIMIT WILL DAMAGE THE
MOTOR.
NOTE: Use JOHN DEERE carbon brush No. 21 indicated in Fig. 4.
a. Replacing carbon brushes:
Remove the brush caps (Fig. 1) with a slotted screwdriver. The carbon
brushes can then be easily removed.
MAINTENANCE AND INSPECTION:
(Fig. 4)
Wear Limit
0.67" (17mm)
0.24" (6mm)
No. of Carbon
brush