How to Replace the Motor and Pinion on a DeWALT Cordless Drill

Motor malfunction? It's time to face the fix. Whether you are a master carpenter or an occasional drill-seeker, eReplacementParts.com provides the parts, procedures and facts you need to fearlessly fix what fails you.

The motor provides power to your DeWALT cordless hammer drill. The most common problem you're likely to encounter (with the motor) will be damage caused by overloading. When this occurs, you'll often see smoke coming from the motor housing and from the side vents on the drill (in the end cap). Another motor-related problem is worn motor brushes. Although this specific motor assembly includes new motor brushes (and solves the problem), the brushes can be serviced independently as needed.

This article provides step-by-step instructions for removing and installing the motor on a DeWALT cordless hammer drill.

Let's get started.   REMOVING THE MOTOR [top] 1. Remove the battery.

Remove the battery from the drill.

  2. Remove the end cap.

Remove the (4) screws from the end cap.

Remove the end cap from the drill.

  3. Remove the gear case assembly.

Remove the (4) screws from the gear case assembly.

Separate the gear case assembly from the motor housing.

  4. Remove the top half of the clamshell (housing).

Remove the (5) screws from the clamshell assembly.

Lift the top half of the clamshell (housing) away from the lower half.

  5. Remove the motor.

Disconnect the wire leads from the terminals on the motor brush holders (one on each side of the motor).

Lift the motor assembly away from the transmission.

  INSTALLING THE NEW MOTOR [top] 6. Transfer the motor adaptor.

Slide the old motor out of the plastic adaptor.

Use a shop rag to wipe excess debris from the adaptor.

Slide the new motor into the plastic adaptor.

Rotate the motor to until the alignment hole (on the motor) engages the plastic tab (inside the adaptor).

Install the plastic wire guide onto the bottom of the motor assembly (the top of the motor is identified with an arrow).

  7. Install the motor.

Align the motor pinion gear with the gears in the transmission and rotate the two components until they engage smoothly.

Rotate the transmission until the gear shift lever (of the transmission) aligns with the “up” arrow (stamped onto the rear of the motor housing).

Install the motor/transmission assembly into the lower half of the housing.

Inspect and shift the components (as necessary) to seat them within the housing.

  REASSEMBLING THE UNIT [top] 8. Reinstall the wire leads.

Connect the wire leads to the terminals on the brush holders (one on each side of the motor).

Tuck the wires into the clips on the wire guide.

  9. Reinstall the top half of the clamshell (housing).

Install the top half of the clamshell (housing).

Secure the clamshell assembly with the (5) screws.

      10. Reinstall the gear case assembly.

Install the gear case assembly.

Rotate the spindle shaft (chuck) until the gear box aligns (snaps into place) with the motor housing.

Secure the gear case to the motor housing with the (4) screws.

  11. Reinstall the end cap.

Install the end cap.

Secure the end cap with the (4) screws.

  12. Reinstall the battery.

Install the battery.

As you just learned, fixing things yourself means more drilling with less billing. Hopefully, this article has restored your ability to drill holes without replacing your whole drill. And that's just the tip of the bit. Our online repair guides can help expand your skills far beyond drills; empowering you to face power tool problems whenever they arise; and to fearlessly fix whatever fails you.

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