Chuck wobble makes it difficult to drill straight holes or drive screws correctly. When the chuck becomes warped or develops a wobble, it might be necessary to replace it with a new chuck. Before replacing a cordless Bosch drill chuck, inspect the chuck spindle once you remove the chuck from the drill. Debris on the spindle thread can cause a wobble. Cleaning the spindle thread or tightening the securing screw is often enough to rectify the problem. However if you do find it necessary to replace the drill chuck, chucks are available from Bosch as well as many home improvement centers. Replacing a cordless Bosch drill chuck is similar to most any other type of drill.
Tools and Material Needed
1/2-inch hex key
Replacement chuck (1/2-inch or 3/8-inch depending upon model)
Remove the battery from the Bosch drill. Depending upon the model you own, the battery either has two tabs on the side or a release button on the back of the battery pack. Press the side tabs toward the battery with your fingers, and pull the battery straight out of the drill. If you have the release tab on the rear, press the tab and slide the battery away from the Bosch drill.
Rotate the clutch sleeve past the numbers to the symbol that resembles a drill bit. This position locks the clutch. During operation this is the position you want the clutch in when you are doing heavy drilling or driving long screws.
Hold the Bosch drill in one hand and rotate the chuck sleeve counterclockwise with your free hand. This opens the chuck jaws. Remove the bit if there is one currently in the chuck. Open the jaws fully and look inside the chuck. There is a small screw at the back of the chuck.
Turn the screw clockwise with a Phillips-head screwdriver, and remove the screw from the chuck. The screw is a reverse thread to prevent it from unscrewing during operation.
Insert the short end of a 1/2-inch hex key into the chuck and tighten the jaws just as you would when you install a drill bit. Hold the Bosch drill on its side on a workbench or table with the chuck hanging over the ledge.
Tap the long end of the hex wrench with a mallet to rotate the chuck counterclockwise. This might take one or two solid taps to start the chuck rotating. Once the chuck rotates, unscrew the chuck from the Bosch drill by hand.
Wipe the spindle head on the Bosch drill with a clean rag. The threads must be clean before threading on a new chuck. Thread the new chuck onto the chuck spindle in a clockwise direction with your hands. Insert the short end of the hex key into the new chuck and tighten the jaws. Give the long end of the hex key a sharp tap with a mallet or hammer to turn the chuck clockwise.
Open the chuck jaws fully and release the hex key. Install the screw into the inside center bottom of the chuck and tighten it with the Phillips-head screwdriver. Remember, it is a reverse thread screw so you must turn it counterclockwise to install and tighten.