An out-of-balance chuck, or one that has faulty jaws, will need replacing. Replacing the chuck on your Hitachi cordless drill is no different than any other drill. You can purchase Hitachi replacement chucks at authorized Hitachi dealers and at some home improvement centers. The drill chuck secures to the drill using a left-hand screw; you will remove the screw in the opposite way you usually remove fasteners.
Press the locking tabs on the side of the battery with your fingers and pull the battery out of the Hitachi cordless drill. The battery is below the handle on your drill.
Hold the ring with one hand and turn the chuck sleeve counterclockwise with your other hand to open the chuck fully. The ring is the portion next to the turning sleeve on the chuck.
Look inside the center of the chuck and locate the Phillips-head screw that secures the chuck to the spindle. This screw is a left-hand screw. Turn the screw clockwise with a Phillips-head screwdriver to remove the screw.
Insert the short end of a large Allen wrench into the chuck just like you would a drill bit. Tighten the chuck around the Allen wrench. Lay the drill on its side with the long portion of the Allen wrench pointing to the left. Strike the Allen wrench hard with a mallet to loosen the chuck from the spindle.
Open the chuck enough to remove the Allen wrench, and turn the chuck counterclockwise to remove the chuck from the drill.
Thread the replacement chuck over the spindle on the drill. You do not need to tighten the chuck, as the force of drilling will tighten the chuck.
Open the chuck jaws fully and secure the chuck to the Hitachi drill with the retaining screw. Place the battery back into the drill handle.