To fix a deadbolt lock, realign the latch with the strike plate by tightening any loose hinge screws and the screws holding the lock to the door, grind the keeper to increase its size, and lubricate the lock. If necessary, grind the deadbolt's bolt to reduce its size.
- Fix the sagging door, and fasten the lock
Check and tighten any loose hinge screws with a screwdriver in order to align the lock latch with strike plate. Check the screws that attach the lock to the door, and tighten them accordingly.
- Widen the keeper
Using a pencil, mark the top of the strike plate, and repeat for the top and bottom of the latch. Open and close the door to check any misalignment between the latch and strike plate by observing the pencil marks. Use a rotary grinder to chop off a part of the keeper's top edge, test the lock, and repeat as needed until the strike plate and latch are aligned.
- Lubricate the lock
Apply a graphite spray to the lock's key, and insert the key into the lock. Twist it repeatedly to lubricate the inner parts of the lock.
- Reduce the deadbolt bolt if necessary
To reduce the deadbolt, remove a 1/8-inch of the bolt with a rotary grinder. Close and open the door to test the lock.