How to Replace the Carbon Motor Brushes on a Makita Grinder

Brushes burned out? It's time to face the fix. Whether you are a master mechanic or a garage-based grinder, eReplacementParts.com provides the parts, procedures and facts you need to fearlessly fix what fails you.

The motor brushes rub against the commutator on the grinder's armature. They're responsible for transferring electricity to the spinning armature. Because they are made of carbon, motor brushes will wear down with normal use. This article provides step-by-step instructions for removing and installing the carbon motor brushes on a Makita grinder.

Let's get started.   REMOVING THE CARBON BRUSHES [top] 1. Remove the side handle.

Unscrew and remove the side handle from the grinder.

  2. Remove the guard.

Loosen the lock-screw on the guard assembly.

Rotate the guard assembly to disengage it from the housing.

Remove the guard from the grinder.

  3. Remove the rear cover.

Remove the (1) screw from the rear cover.

Slide the rear cover away from the motor housing.

  4. Disengage the brush springs.

Use a pick to (gently) lift the brush spring from the back of the carbon motor brush.

Reposition the brush spring alongside the motor brush (against the brush holder).

  5. Remove the carbon motor brush.

Disconnect the brush wire from the terminal on the brush holder.

Slide the motor brush out of the brush holder.

Repeat this step to remove the second brush (on the opposite side of the grinder).

    INSTALLING THE NEW CARBON BRUSHES [top] 6. Install the carbon brushes.

Install the new motor brush into the brush holder.

Connect the brush wire to the terminal on the holder.

Repeat this step to install the second carbon brush (on the opposite side of the grinder).

  REASSEMBLING THE UNIT [top] 7. Re-engage the brush springs.

Use a pick to reposition the brush against the motor brush.

Repeat this step to re-engage the second brush spring.

  8. Reinstall the rear cover.

Visually inspect the wires for potential “pinch-points” and adjust/tuck the wires as necessary.

Slide the rear cover onto the motor housing.

Secure the rear cover with the screw.

  9. Reinstall the guard.

Install the guard assembly onto the grinder.

Rotate the guard assembly to engage the mounting plate.

Secure the guard with the (1) screw.

    10. Reinstall the side handle.

Install the side handle onto the grinder.

Tighten the side handle until secure.

You can't place a value on a job well done, unless you did it yourself. (Which you did.) Now you can place that value back into your own pocket. (Or into your business.) Not only did you refine your grinder at a fraction of the cost of replacement; you have expanded your skills far beyond the daily grind.

Find your next grind here.   [top]