Hammer Drill: Grinding or Squealing Sound
If your hammer drill is making a grinding or squealing sound, check the carbon brushes, bearings, armature, and gears. Once you have located the part that is causing the problem, read our repair guide for tips on fixing your hammer drill yourself. It might actually be a lot easier then you think. Reference your owner's manual for instructions relating to your model.
Remove any shafts and hold-down brackets so you can remove the armature. Remove the brush holders. On other models, remove the brushes simply by removing the hold-down clip and pulling the brush out of the holder. Pull the motor up and slide the armature free of the motor. Slide the new armature into the field and place the...
Remove any shafts and hold-down brackets so you can remove the armature. Remove the brush holders. On other models, remove the brushes simply by removing the hold-down clip and pulling the brush out of the holder. Pull the motor up and slide the armature free of the motor. Slide the new armature into the field and place the motor back down in the case. Reinstall the brushes in the holders and reapply the hold-down clip or brush holders. Reinstall all shafts and fasten any hold-down brackets. Reassemble the case and reattach the handle.
Replacing spindle bearings will vary on all models, as they are slightly different. To replace spindle bearings, remove the cam plate, leaf spring, change plate, steel ball, gear and the retaining ring. Use a bearing separator, or puller, to remove the bearing. If you are using a separator, once it is installed around the bearing, place it on top of an open bench vice. Place a punch on top of the shaft and tap it with a hammer to free the bearing. Place the shaft in a vice to hold it steady, but not too tight, as you do not want to damage the shaft. Install the new bearing onto the spindle by using a socket that only makes contact with the inner race of the bearing. This is to avoid any damage to the bearing. Tap in place with a hammer. Reinstall the retaining ring, gear, steel ball, change plate, leaf spring and cam plate. Reinstall the spindle assemble into the drill case and reassemble the case back together. Reattach the handle back on the hammer drill.
Secondary shafts usually have the bearing on the end of the shaft. Remove the bearing using a separator or a puller. When using a separator, once it is install around the bearing, place the separator on a bench vice. Open up the bench vice enough so only the separator is making contact. Place a punch on the shaft and hit the punch with a hammer, until the bearing becomes loose. Place the shaft in the bench vice, but not too tight to avoid damage to the shaft. Place the bearing on the shaft and use a socket that makes contact with the bearing inner race to avoid any damage to the bearing. Tap in place with a hammer. Reinstall the shaft in the hammer drill’s case and reassemble the case back together. Reattach the handle.
Inspect the brushes for signs of breakage. If you notice a piece is missing, make sure it is not wedged in the drill somewhere, causing the squealing or grinding sound – especially check around the commutator. Spin all moving parts and listen carefully. Replace any broken, or worn...
Inspect the brushes for signs of breakage. If you notice a piece is missing, make sure it is not wedged in the drill somewhere, causing the squealing or grinding sound – especially check around the commutator. Spin all moving parts and listen carefully. Replace any broken, or worn out, brushes. Brushes less than 1/8 of an inch are worn out and need to be replaced. Install the brushes in the holder, making sure the tab locks in place. On other models, slide the brush in the holder and fasten the hold-down clip. Install the brush holders back in the case, using a small screwdriver to hold the brush down, giving you clearance of the commutator. Reassemble the case back together, securing it with the fasteners and reattach the handle.
With the case open, examine all the gears by turning them, looking for damage. Remove any hold-down brackets, if applicable. Remove the spindle assembly from the drill. Remove the cam plate, leaf spring, change plate, steel ball and gear with the keyway. Some models may have more than one gear here. Remove and install the new gear with the keyway, ensuring the keyway stays in place during installation. Reinstall the steel ball, change plate, leaf spring and cam plate. Some drills will have a secondary shaft with gears. Depending on the model, repair procedures will vary. To replace a...
With the case open, examine all the gears by turning them, looking for damage. Remove any hold-down brackets, if applicable. Remove the spindle assembly from the drill. Remove the cam plate, leaf spring, change plate, steel ball and gear with the keyway. Some models may have more than one gear here. Remove and install the new gear with the keyway, ensuring the keyway stays in place during installation. Reinstall the steel ball, change plate, leaf spring and cam plate. Some drills will have a secondary shaft with gears. Depending on the model, repair procedures will vary. To replace a gear on the secondary shaft, remove any bearings with a puller or separator. Take out any retaining rings, washer, and the old gear and then install the new one with the keyway.
Reassemble everything back on the shaft in reverse order. Use a socket that makes contact with the bearing inner race when reinstalling to avoid damage to the bearing. Tap the socket with a hammer to set the bearing in place. Reinstall back in the drill case and fasten any hold-down brackets. Reassemble the case back together and then reattach the handle.