How to Replace the Armature Bearing on a Makita Power Scraper

Power tools use many bearings to allow various components to rotate. Over time, a ball bearing will wear and begin to fail. A bearing that is failing will usually give warning, often with a squeaking or squealing sound.

Let's get started.

REMOVING THE ARMATURE BEARING   1. Remove the top half of the handle.

a. Remove the screws securing the top half of the rear handle.

b. Lift the top half of the handle away from the unit.

  2. Remove the rear cover.

a. Remove the screws securing the rear cover.

b. Remove the rear cover from the unit.

  3. Remove the motor brushes.

a. Use a large screwdriver to remove the brush caps.

b. Remove the motor brushes from the brush holders.

  4. Remove the motor housing.

a. Remove the four screws securing the motor housing to the crank housing.

b. Use a screwdriver to separate the motor housing from the crank housing (if necessary).

c. Slide the motor housing assembly away from the crank housing.

  5. Remove the armature.

a. Remove the armature assembly from the crank housing. If the armature is still inside the motor housing, use a screwdriver (as-needed) to gently pry the armature up and out of the motor housing.

  6. Remove the bearing.

a. Use a bearing puller to remove the commutator-end bearing from the armature.

INSTALLING THE NEW ARMATURE BEARING

  7. Install the bearing.

a. Place the armature on the anvil-portion of a bench vise (with the commutator-side facing up).

b. Install the new bearing onto the shaft of the armature.

c. Use a socket and hammer to tap (and seat) the new bearing on the armature shaft.

REASSEMBLING THE UNIT

  8. Reinstall the armature.

a. Install the armature into the crank housing.

  9. Reinstall the motor housing.

a. Install the motor housing onto the crank housing (over the armature).

b. Secure the motor housing with the four screws.

  10. Reinstall the motor brushes.

a. Install the motor brushes into the brush holders.

b. Compress the brush springs into the holders.

c. Secure the motor brushes with the brush caps.

  11. Reinstall the rear cover.

a. Install the rear cover.

b. Secure the rear cover with the screws.

  12. Reinstall the top half of the handle.

a. Tuck all exposed wires into the lower handle.

b. Install the top half of the handle.

c. Secure the top half of the handle with the screws.