In many door designs the deadbolt lock is the only lock on the door, so a sticking deadbolt causes multiple problems. Deadbolt locks are locks that "bolt" the door to the door frame by turning a knob that moves a bolt into or out of a hole protected by a metal plate in the frame. Many plausible explanations exist for a stuck deadbolt as well as a few methods to free the bolt so the door can be opened. Proper routine maintenance of the bolt can help prevent the deadbolt from resticking in the future.
Foundation and house shifting are common problems during rainy seasons or during extreme temperature shifts. When the foundation and house shift, doors become misaligned with the latch plate in the door frame. If this shifting occurs when the deadbolt is extended, the deadbolt may become stuck under the pressure of the door's weight. Wood doors can warp due to moisture or temperature, which also places pressure onto the bolt extended into the latch plate. The deadbolt itself may be the problem. Rust and moisture can cause the metal to corrode. These rough patches may cause the bolt to stick when extended into the latch plate. Dust and grime can accumulate in the deadbolt's mechanisms, causing the bolt to "freeze up" when extended.
To free a stubborn deadbolt, try the least complicated methods first. Lean against the door. Turn the lock knob to see if pressure will free the bolt. Attempt to lift or pull the door while turning the lock's knob. Sometimes a stuck bolt needs pressure applied in a different direction (pushing, lifting or pulling) to free it. Insert the nozzle of a household lubricant between the door and the latch plate. Spray the lubricant over the bolt and anything else you can see. Allow the lubricant to rest for about two minutes to dissolve any substance hindering the bolt's movement. Wiggle the knob back and forth as much as it will allow to work the lubricant into the mechanisms. While you wiggle the lock, slip a credit card between the door and the latch plate and attempt to slide it between the bolt and the latch plate should the bolt wiggle free. Use a screwdriver or the card to push the bolt out of the latch plate.
Removal of Door and/or Deadbolt
Use a mallet or hammer to tap the door's hinge pins from the hinges. Remove the door, pulling it out and away from the latch plate on the frame. Test the deadbolt. If the deadbolt is working, the problem lies with the door alignment. Try removing the latch plate and adjusting the position. A new hole will need to be chiselled or adjusted to fit the bolt. Use wood putty to fill in the previous screw holes. You may have to reinstall the door and test the deadbolt alignment several times before getting it right. If the deadbolt itself is frozen and household lubrication fails to loosen it, remove the screws holding the deadbolt to the door. Reinstall the door, and install a new deadbolt.
Stuck Deadbolt Preventions
Lubricating the deadbolt with each changing season will keep the bolt sliding smoothly. Keeping an eye on a shifting door frame and how it affects the door's alignment will prevent surprise problems. Readjust the hinge positions on the door so the door hangs correctly and the deadbolt aligns with the latch plate.