Tools & Materials
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 motor brushes.
a. Use a large screwdriver to remove the two brush caps.
b. Remove the motor brushes from the brush holders.
2. Remove the armature assembly.
a. Remove the (4) screws securing the gear housing to the motor housing.
b. Separate the gear housing (and the armature) from the motor housing.
c. Hold the armature assembly with one hand and use a rubber mallet to gently tap the gear housing away from the armature assembly.
3. Remove the armature bearing.
a. Use a bearing separator to remove the bearing from the armature assembly.
INSTALLING THE NEW ARMATURE BEARING
4. Install the armature bearing.
a. If the plastic insulation washer came off during the previous step, install it onto the armature shaft now.
b. Place the new bearing onto the armature shaft.
c. Locate a socket that is approximately the same diameter as the inner race of the new bearing.
d. Position the socket on the inner race of the bearing.
e. Use a hammer to tap the socket and press the new bearing onto the armature shaft.
REASSEMBLING THE UNIT
5. Reinstall the armature assembly.
a. Install the (fan-side) of the armature into the gear housing.
b. Rotate the armature (as-necessary) to align the pinion gear with the bevel gear inside the housing.
c. Use a rubber mallet to tap the armature (as-necessary) and seat the (fan-side) bearing in the gear housing.
6. Reinstall the gear housing (with the armature).
a. Install the gear housing (and armature assembly) into the motor housing.
b. Secure the gear housing to the motor housing with the (4) screws.
7. Reinstall the motor brushes.
a. Install the motor brushes into the brush holders.
b. Secure the brush holders with the brush caps.