changed the pad on my 20v sander and now it makes a loud clicking noise every rotation

Diagnosis

The loud, rhythmic clicking noise occurring after a pad change on the DeWalt DCW210B is almost always caused by a mechanical interference between the sanding platen and the dust collection shroud. This typically happens because the replacement pad—especially if it is an aftermarket or non-OEM part—is slightly thicker or has a different profile than the original. When the motor spins the pad in its random orbit pattern, the edge of the pad or the hook-and-loop backing strikes the inner rim of the plastic dust port once per rotation. Alternatively, the clicking is caused by an improper seat of the pad on the spindle. If a small piece of sawdust or a fragment of the old adhesive backing has migrated into the spindle recess, the new pad cannot sit flush. This creates a slight tilt or "wobble." Because the DCW210B uses a high-frequency orbital motion, even a millimeter of misalignment causes the pad to collide with the housing, creating a sharp, metallic or plastic clicking sound that accelerates as you increase the speed trigger. To confirm this, remove the dust bag and run the sander; if the noise persists, the issue is internal to the pad seating; if it stops, the pad is rubbing against the shroud.

How to Fix It

To resolve the interference and eliminate the clicking, follow these precise steps to reset the pad alignment:

1. Power down the tool and remove the 20V Max battery to ensure total safety during the mechanical adjustment.
2. Using a Phillips head screwdriver, remove the center mounting screw from the sanding pad.
3. Lift the pad off and use a can of compressed air or a vacuum to thoroughly clean the spindle head and the recessed cavity where the pad sits. Ensure there are no grit particles or dried glue remnants preventing a flush fit.
4. Inspect the center alignment pin (the plastic nub) on the underside of the new pad. If it is deformed or too long, carefully trim it with a utility knife so it doesn't bottom out before the pad shoulder hits the tool base.
5. Place the pad back onto the spindle, pressing down firmly with your palm to ensure the pad is fully seated in the recess.
6. Insert the mounting screw. Tighten it until snug, but do not over-torque it. Over-tightening can warp the plastic backing of the pad, which actually increases the likelihood of the edges hitting the shroud.
7. Reinstall the battery and run the tool at the lowest speed setting to verify the noise has ceased before ramping up to full power.

If That Didn't Work

• Verify Pad Compatibility: If you are using a third-party "universal" pad, it may be 1-2mm too thick for the DCW210B's tight tolerances. Switch back to the genuine DeWalt replacement pad (Part #D25272) to see if the clicking disappears. Aftermarket pads often lack the precise bevel on the outer edge required to clear the dust shroud.
• Inspect the Bearing Housing: If the clicking sounds internal (metallic) rather than external (plastic), the spindle bearing may have shifted during the pad change. Remove the pad entirely and run the tool for 2 seconds. If it still clicks without a pad, the bearing has failed or the spindle is bent, requiring a professional motor assembly replacement.
• Check the Dust Shroud Alignment: Inspect the plastic dust collection port for cracks or warping. If the shroud has been bumped or cracked, it may have shifted inward. Use a small file to gently shave away the inner plastic rim of the shroud where the pad is making contact.
• Reseat the Backing Plate: Remove the screw and slightly loosen the housing screws on the bottom of the unit. Sometimes the entire base plate shifts slightly during a rough pad change; loosening and re-tightening the chassis screws can re-center the spindle.

Heads Up

• Avoid using "extra-thick" or "heavy-duty" aftermarket pads, as they frequently interfere with the DCW210B's dust extraction system and can cause overheating of the orbital motor.
• Always clean the spindle area before every pad change; a single grain of sand trapped under the pad can cause an imbalance that vibrates the tool and wears out the bearings prematurely.
• Do not use power drills to tighten the pad screw; the plastic threads in the backing plate can strip easily, leading to the pad flying off during high-speed operation.
• Periodically check the hook-and-loop surface for "pilling." If the fabric is worn down, the sanding disc can shift, causing the pad to tilt and create the same clicking noise as a misaligned pad.