Makita 7104L Technical Information page 3

R
epair
[3] Repairing Motor Section
Armature and Field can be replaced without disassembling Gear housing section.
[3]-1. Disassembling Motor Section
Remove Carbon brushes from the machine.
Motor housing complete can turn freely by separating four M5x80 pan head screws from the machine.
However, the last one is difficult to be unscrewed because the tensile force of Tension spring 20 affects it through Chain
bar holder and Rotor holder. Therefore, push Handle to counterclockwise direction as mentioned in Fig. 1 to remove the
last M5x80 pan head screw.
Next, Turning Motor housing complete clockwise as shown in Fig. 2 so that the tensile force of Tension spring 20 can be
removed.
Fig. 1
Handle (switch installation side)
Four Pan head screws M5x80
Push the Handle
in the direction of
arrow.
Chain bar holder
Strike one end of Spring pin 5-12 using Spring pin extractor 5.0
(Makita part No. 1R309) and plastic hammer as shown in Fig. 3
until the other end comes out of the hook of Rotor holder.
And then, pull out the Spring pin 5-12 from the opposite side
using pliers. Pull out Motor housing complete backward while
turning it. Move on to the step for Motor replacement.
[3]-2. Reassembling Motor Section
Perform the disassembling procedure in reverse of the assembling steps.
The reassembling work can be successfully performed even if Tension spring 20 shrinks to the original size.
Drive Spring pin 5-20 into the hole of Rotor holder's hook upward from the bottom so that the upper end protrudes by 4mm
for the stopper of Tension spring 20. Install Armature from Chain bar holder side. It is useful as a guide when Motor
housing complete is installed.
Hook one end of Tension spring 20 in the hole of Grip holder L as shown in Fig. 4 after inserting Motor housing section in
Rotor holder. Chain cover should be vertical against ground. And both Motor housing and Rotor holder should be paralleled
to the ground while pulling Tension spring 20 using Handle as described in Fig. 5. At this time, while pressing Motor
housing section with knee, tighten four M5x80 pan head screws. This is to prevent the Motor housing section from slipping
off.
Fig. 4
The other end of Tension Spring 20
Rotor holder
Tension
Spring 20
Grip holder L
One end of Tension Spring 20
Motor housing
Hook of Rotor holder
for Tension spring 20
Spring pin 5-12 for the stopper
of Tension spring 20
Fig. 2
Fig. 3
One end of Spring pin 5-12
Hook of Rotor holder
for Tension spring 20
Spring pin
extractor 5.0
Spring pin 5-12 for the stopper
of Tension spring 20
Plastic hammer
Fig. 5
Press Motor housing with knee.
Push Handle to
the direction of
arrow.
P 3 / 8
Turn the Motor
housing complete
in the direction of
arrow.
Motor
housing
Check these flat
areas is parallel
to the ground.
Chain bar holder
should be vertical
against ground.