Tools & Materials
Brush holder hammered? It's time to face the fix. Whether you are a master carpenter or an occasional drill-seeker, eReplacementParts.com provides the parts, procedures and facts you need to fearlessly fix what fails you.
The brush holder on your Makita cordless drill is an assembly consisting of two metal brush holders, a plastic card that they are attached to, two brush springs, and a couple of wire leads.
The assembly holds the carbon motor brushes at the proper location on the armature, allowing them to transfer electricity to it. The brush springs apply tension to the brushes, ensuring constant contact with the armature. The wire leads provide electricity (from the switch) to the brush holders.
Typically, the brush holder assembly only needs to be replaced if the drill's motor has been overheated. Excess heat can melt or warp the plastic brush card. The brush springs, if overheated, will lose their tension. Look for signs of melted plastic or discolored brush spring wires.
This article provides step-by-step instructions for removing and installing the brush holder on a Makita cordless hammer drill.
Let's get started. REMOVING THE BRUSH HOLDER [top] 1. Remove the battery.
Remove the battery from the drill.
2. Remove the rear cover.
Remove the (2) screws.
Remove the rear cover from the drill.
3. Split the housings.
Remove the screws from the top half of the housing.
Lift the top half of the housing away from the unit.
4. Remove the motor brushes.
Use long-nosed pliers to retract the brush spring from the back of the motor brush.
Use a small screwdriver to disengage (pry) the brush clip from the brush holder.
Slide the carbon brush out of the brush holder.
Repeat this step to remove the second motor brush.
5. Remove the motor and gear assembly from the housing.
Partially lift (pry) the heat sink away from the motor.
Lift the motor and gear assembly (as a single unit) slightly out of the housing.
Disengage the brush card from the armature assembly.
Remove the speed-change lever from the motor and gear assembly. (Be careful not to lose the two springs situated inside the speed-change lever.)
6. Remove the brush holder.
Lift the switch assembly out of the housing.
Note the location of the wires prior to disassembly.
Disconnect the (2) brush holder wires from the switch assembly.
Remove the brush holder from the unit.
INSTALLING THE NEW BRUSH HOLDER [top] 7. Install the brush holder.
Connect the (red) wire (on the new brush holder) to the (M1) terminal on the switch.
Connect the (black) wire (on the new brush holder) to the (M2) terminal on the switch.
REASSEMBLING THE UNIT [top] 8. Reinstall the switch.
Align the notch on the forward/reverse change lever with the post on the switch.
Install the switch (and F/R change lever) into the lower half of the housing.
Tuck the switch wires into the channels on the housing.
9. Reinstall the motor and gear assembly.
The notch on the yoke unit is designed to engage the plastic tab on the lower half of the housing. Rotate the yoke unit (as necessary) to ensure alignment of these components.
Reinstall the brush card over the armature.
Install the motor and gear assembly (as a single unit) into the lower half of the housing.
Manipulate the components (as necessary) until: 1) the notch on the yoke unit engages the tab on the housing; 2) the speed-selector switch is properly seated within the channels on the housing; and 3) the brush card is properly seated in the lower half of the housing.
10. Reinstall the heat-sink.
Install the heat-sink into the lower half of the housing.
Verify that the wires (extending from the heat-sink) are positioned on the switch-side of the plastic post (not on the motor-side).
11. Reinstall the top half of the housing.
Inspect all of the wires for potential pinch-points; make adjustments as necessary.
Reinstall the top half of the housing.
Secure the housing with the screws.
12. Reinstall the motor brushes.
Retract the brush spring from the brush holder.
Install the motor brush into the brush holder.
Secure the brush clip to the brush holder.
Reposition the brush spring onto the motor brush.
Repeat this step to reinstall the second motor brush.
13. Reinstall the rear cover.
Install the rear cover.
Secure the rear cover with the (2) screws.
14. Reinstall the battery.
Install the battery.
As you just learned, fixing things yourself means more drilling with less billing. Hopefully, this article has restored your ability to drill holes without replacing your whole drill. And that's just the tip of the bit. Our online repair guides can help expand your skills far beyond drills; empowering you to face power tool problems whenever they arise; and to fearlessly fix whatever fails you.