How to Replace the Armature in a Milwaukee Cordless Drill

If broken drills and service bills are boring holes in your budget; it's time to face the fix. Whether you are a master craftsman or an occasional drill-seeker, eReplacementParts.com provides the parts, procedures and facts you need to fearlessly fix what fails you.

The armature is the inner portion of the drill motor. The assembly consists of two bearings and the gear that links the armature to the transmission. Symptoms of a bad armature include excessive sparks or smoke coming from the sides of the drill during use. Replacing the armature is easy to do, and this article will guide you through the steps required.

Let's get started.   THE FACTS | THE FIX | THE FINISH REMOVING THE ARMATURE  [top] 1. Remove the battery from the drill.

      2. Remove the end cap.

Remove the end cap retaining screws.

Remove the end cap.

      3. Remove the top half of the housing.

Remove the four screws securing the transmission to the housing.

Remove the retaining screws from the top half of the housing.

Remove the top half of the plastic housing.

      4. Disengage the brush springs.

Use a pick or small screwdriver to disengage the brush springs (there are tiny notches on the backs of the brush holders, which can be used to secure the springs until they are re-engaged).

    5. Remove the armature.

Lift the motor and gear case assembly slightly out of the housing.

Separate the motor from the gear case assembly.

Slide the brush card off the armature.

Remove the motor assembly from the housing.

Separate the field from the armature.

  INSTALLING THE NEW ARMATURE  [top] 6. Install the armature.

Slide the new armature into the field (ensure that the notches on the field are facing the front of the drill).

Reattach the motor to the gear case assembly (insert the gear-end of the motor into the transmission and ensure that the bearing is completely seated within the transmission housing).

  REASSEMBLING THE UNIT  [top] 7. Reinstall the gear case/motor assembly into the housing.

SPECIFIX: Note that the field contains notches on both sides. These notches must align with the tabs on the plastic housing. Also, there is a tab on the transmission, which must be aligned with the notch in the housing.

Install the gear case/motor assembly into the housing.

      8. Reinstall the brush card.

Slide the brush card onto the armature.

Align the edge of the brush card with the slot in the housing.

      9. Reinstall the top half of the housing.

Use a small screwdriver to tuck any exposed wires into the channels along the housing.

Install the top half of the housing.

Secure the housing with the screws.

Secure the transmission assembly to the housing with the four screws.

      10. Re-engage the brush springs.

Use a pick or small screwdriver to re-engage the brush springs.

      11. Reinstall the end cap.

Install the end cap.

Secure the end cap with the four screws.

  THE FACTS | THE FIX | THE FINISH

As you just learned, fixing things yourself means more drilling with less billing. Hopefully, this article has helped restore your ability to drill holes without replacing your whole drill. And that's just the tip of the bit. Our Follow-and-Fix field guides can help expand your skills far beyond drills; empowering you to face power tool problems as they arise and to fearlessly fix whatever fails you. Find your next fix here.   [top]