background image

P 2/ 7

R

epair

CAUTION: Remove the battery and the bit from the machine for safety before repair/ 
                     maintenance in accordance with the instruction manual! 

[1] NECESSARY REPAIRING TOOLS

[2] LUBRICATIONS

[3] DISASSEMBLY/ASSEMBLY
[3]-1. Keyless Drill Chuck

Hex wrench 8

Removing / Installing Drill chuck

Plastic hammer Removing Drill chuck

Description

Use for 

The components of Gear ass’y has been lubricated in Makita plant and assembled under strict quality control. Therefore, 
it is recommended to replace Gear ass’y without disassembling in repair.

Note

: When replacing Gear ass’y, begin by removing Keyless drill chuck.

          As long as the repairing does not concern Gear ass’y, it is not necessary to remove Keyless drill chuck. 

(1) Remove M6x22 Flat head screw. (

Fig. 1

)

(2) Preset the machine as illustrated in 

Fig.2

.

(3) Hold the machine firmly and pull the switch trigger slowly and carefully.

Note

: 1) Pay attention that the machine except Keyless drill chuck starts revolving with strong force. Do not pinch your 

               hand between the moved machine and Vise in this step.
          2)  If it is impossible to remove Keyless drill chuck, use 1R359 (Chuck removing tool) to remove it. Refer to Makita 
               repair tool list.    

1) Turn Keyless drill chuck clockwise until it sits on the end of the threaded portion of Spindle.
2) Fix the short portion of Hex wrench 8 to Drill chuck, and clamp the long portion of Hex wrench 8 in Vise.
3) Set Speed change lever in the low speed mode and F/R change lever in the Forward (clockwise) rotation mode. Then
    Install Battery.
4) Hold the machine firmly and pull the switch trigger to rotate Spindle until the motor is locked.
    

Note

: Pull the switch trigger so that Spindle reaches full speed in one second.

    

Important

: Be sure to release the switch trigger just after Spindle is locked.

5) Secure Keyless drill chuck with M6x22 Flat head screw by turning 

counterclockwise 

with impact driver.

    

Note

: If you reuse the removed M6x22 Flat head screw, apply adhesive (ThreeBond 1321B/ 1342, Loctite 242) to 

              the threaded portion. Makita genuine M6x22 Flat head screw for securing Keyless drill chuck is threadlocker 
              screw.  

DISASSEMBLING

ASSEMBLING

Hex wrench 8

Note

: Hold the flat surface 

           of Hex wrench 8.

Vise

Clamp the long portion
of Hex wrench 8 in Vise.

Vise

Fig. 1

Fig. 2

M6x22 Flat head screw
with adhesive

Note

: Pay attention to the

          turning direction.

Open the jaws of Keyless drill chuck fully
and remove M6x22 Flat head screw by 
turning 

clockwise

.

If it is difficult to remove the screw with 
slotted screwdriver, use cordless impact 
driver. 

Set F/R Change lever in 
the reverse mode. 

Set Speed change lever 
in the low speed mode. 

Set Change ring 
in the drill mode. 

Hold Hex wrench 8
by tightening the jaws 
of Keyless drill chuck.

Install Battery.

Summary of Contents for 8391D

Page 1: ... m in lbs Torque setting Steel Wood Soft joint Hard joint No load speed min 1 rpm Cell Voltage V Capacity Ah High Net weight with Battery 1822 kg lbs Low Max output W Ni Cd 18 1 3 2 0 Yes Yes Yes 2 speed Yes 2 3 5 1 13 1 2 36 1 7 16 Masonry 13 1 2 16 stage drill mode Clutch torque setting N m in lbs 1 0 4 0 9 35 38 340 27 240 42 370 0 1 300 0 400 1 5 13 1 16 1 2 230 Impacts per minute min 1 ipm Hi...

Page 2: ...tion of Spindle 2 Fix the short portion of Hex wrench 8 to Drill chuck and clamp the long portion of Hex wrench 8 in Vise 3 Set Speed change lever in the low speed mode and F R change lever in the Forward clockwise rotation mode Then Install Battery 4 Hold the machine firmly and pull the switch trigger to rotate Spindle until the motor is locked Note Pull the switch trigger so that Spindle reaches...

Page 3: ...er ass y from Gear ass y Gear ass y Remove Gear ass y Speed change lever ass y and DC motor with Switch from Housing set L as illustrated above Disassemble Housing set R by unscrewing 3x16 Tapping screws 9 pcs Pull off Gear ass y while turning it clockwise viewed from DC motor side Now Gear ass y can be replaced Motor bracket Motor bracket Remove DC motor from Motor bracket by unscrewing M3x6 Pan ...

Page 4: ... assembling Speed change lever ass y make sure two Compression springs are assembled to its bottom in advance Fig 9 2 Fit the protrusion of Gear ass y into Compression spring 4 in Speed change lever ass y Fig 10 3 After mounting set Speed change lever ass y to low speed mode or high speed mode Fig 11 Motor bracket DC motor none of protrusion side protrusion of Gear ass y 3 3 Speed Change Lever ASS...

Page 5: ...itch Fit the protrusion of Switch to the prong of F R Change lever Prong Housing set L Before assembling Gear ass y and DC motor Leaf spring has to be mounted to Housing set L as illustrated in Fig 12 F R Change lever can be assembled to Switch as illustrated in Fig 13 ASSEMBLING Fig 13 Leaf spring 3 5 F R Change Lever Switch Protrusion F R Change lever ...

Page 6: ...Lead wire red to Terminal M1 Lead wire black to Terminal M2 Switch viewed from Housing set L side Switch viewed from Housing set R side red point mark Connecting of Lead Wire red to DC Motor Connect Lead wire red to the Terminal marked with red point mark Housing set R side The terminal of this protruded side is plus Switch Battery holder Switch ...

Page 7: ...f the machine Front side Battery holder Switch s lead wire black Switch s lead wire red Battery holder Rear side Housing set L Housing set R Side This protruded Side is fitted to Housing set R Front side Rear side Switch s Lead wire black Switch s Lead wire red Fig D 2A Red point mark Connect Switch s Lead wire black to Battery holder while facing it to rear side Connect Switch s Lead wire red to ...

Reviews: