Dewalt’s DC901 is one of a handful of Dewalt drills that uses a self-tightening, Loctited chuck. Whether for better or for worse, the nature and design of this chuck eliminates the need for the chuck-screw that sits inside the center of most ordinary drill chucks. Because this drill lacks that screw in favor of dab or two of Loctite, the chuck on the DC901 is a little bit trickier to remove and replace. Mind you, only a little bit trickier, and even less so when you are armed with the right steps.
To remove the chuck from Dewalt’s DC901, you want to first ensure that the hammer drill itself is in all the right places, positions, settings, and etc. First, ensure the tool is in low-gear. This is a stronger torque gear that is simply better suited for the intense wrenching the chuck is about to encounter. You will also want to ensure the tool is set to drill-mode, that the clutch is set at clutch setting “22,” and that the drill-chuck itself is entirely open. These few steps, while simple, are vitally important to the overall process and will literally make or break your ability to remove the chuck from this particular hammer drill.
The next step in removing the chuck from Dewalt’s DC901 requires a vise or vise-like mechanism to clamp the hammer drill’s chuck as you wrench on the body of the tool. If you don’t have access to this kind of equipment, it is advised that you take the drill to a certified repair shop, or, at least, borrow someone else’s. If you do have access this kind of equipment, tightly clamp the hammer drill-chuck (mind you, clamp just the chuck and leave the body of the DC901 entirely free) into the vise. If, for one or another reason, you wish to avoid any scratching or injury to the chuck, wrap a shop rag around it before clamping.
Using just your own body strength, whip the drill in a counterclockwise direction until the Loctite that secures this particular chuck breaks free. You will hear a “pop” and you will feel a significant decrease in the overall tightness of the chuck. If after a few whips the Loctite remains persistently un-brocken, you can heat it up with a heat-gun or blow-dryer. This should render the glue pliable enough to break the seal more easily.
Once you hear that “pop,” remove the DC901 from the vise and, using counterclockwise twists, simply hand-twist the chuck from the drill. It should now easily remove with only a few complete twists.
To reinstall a new chuck on the DC901 (the chuck’s part number is 330075-90), simply dab a dob (really, only a small dob) of Loctite onto the hammer drill’s threaded chuck shaft. Twist and hand-tighten the chuck onto the shaft in a clockwise motion. Allow the glue to set and secure to the threads for at least one-hour before using your DC901 in any capacity whatsoever. I reiterate, while it is smart to allow the Loctite to set for up to 24-hours, you must let it set for, at very least, one hour before using it.
Source by Mallory Kramer