DeWalt miter saws are extremely durable tools that tend to last a lifetime. But anything with moving parts will tend to wear over time. If your DeWalt saw is experiencing a loss of power, intermittent power, or if you're seeing sparks/smoke come out of the motor housing there's a good chance your armature is ready for replacement. As the brushes and armature come in contact with each other these parts slowly wear down. A brush inspection is the first place to start with problems like these, but keep in mind a damaged brush often indicates a problem with the armature, so we recommend replacing these together. Replacing the armature is a very simple process, just remove the motor housing and the armature will be located underneath.
Step 1: Order parts. The armature for the DW704 & DW705 comes as a kit with a new motor housing, armature bearing and the armature itself.
Armature Kit for DW704 & DW705 types 4A-7:
Step 2: Remove brushes from either side of motor end cap using a flat head screwdriver. Worn brushes will be visually obvious. It is recommended to use new brushes whenever installing a new armature, even if they don't appear to be worn.
Step 3: Remove motor end cap.
Step 4: Undo the 4 bolts holding the motor housing in.
Step 5: Remove screws on the handle assembly, then the motor housing and handle assembly will slide off together.
Step 6: Remove old armature. It can be locked in pretty tight, use a light amount of force and wiggle different directions until it releases from the saw gears.
Step 7: Install new armature. This is simple, just put it in the same way it came out.
Step 8: Resecure handle assembly, motor housing and end cap.
Step 9: Replace brushes, test power.
And that's it! Replacing the armature can extend the life of your DeWalt miter saw indefinitely and will save you hundreds of dollars on a replacement. If you have any questions about the process, try watching this how-to video created by mmToolParts on replacing the armature in a DW704 or DW705.