- Deadbolt locks work via a tumbler system, where the key's indentations and ridges press against pins that are forced into a position that releases the bolt to slide back and forth. When the pins are frozen into position the bolt will not move. The problem may be mechanical, which means replacing the cylinder core, or just an accumulation of grime and oil that is blocking the pins.
- A Phillips screwdriver is all that is needed to remove a Schlage deadbolt from the door to check the inner mechanism. Remove the two long screws from the inside of the doorway that hold the front lock plant to the outside lock plate. The two pieces pull out with finger pressure, followed by the bolt from the side of the door. Look for any obstructions that may interfere with the turning of the bolt, such as a broken piece of metal or a missing pin.
- Clean the pins and all other areas with cotton swabs dipped in rubbing alcohol or other cleaning solution. Wipe away any dirt or oil that is visible. If the lock has never been cleaned it may take vigorous scrubbing to remove some debris. If your climate is generally warm, you can apply a very light film of sewing machine oil with a cotton swab to the inside mechanism after cleaning, but if you experience cold weather it is best to use a spray designed for keeping locks working. These are available at hardware stores.
- Put the lock back together with the screws and use both the level and the key to turn the bolt to see what happens to the inner pins. If the pins turn easily and the bolt slides back and forth, then replace the lock on the door. If the bolt is still frozen you will have to buy a new cylinder, or inner core, to replace the existing one. Any locksmith and many larger hardware stores will have one. Schlage makes it easy to adjust the new core so that your old key fits. The new core merely drops in place of the old one before the lock is replaced on the door.