How To Replace a Deadbolt Lock
There are two types of deadbolt locks—externally mounted and internally mounted. The external deadbolt is much easier to install than the internal; however, it offers less security. An internal deadbolt, because of the tougher hardware and the long bolt also provides much more security than a typical lockset that is standard for exterior doors.
When replacing a deadbolt, you may be able to purchase a keyed lock (also called a double-cylinder lock), which offers extra security. With a keyed deadbolt, a key is required on both sides of the door. If your door has a window and a home intruder breaks it, the keyed lock will prevent them from reaching through and unlocking the door. However, during an emergency this type of lock can be dangerous. If the key cannot be found and people can’t get out, the hazard is obvious. Some communities have restrictions against the use of such locks, check with your local building department. If you install a keyed lock, always keep the key in the same place and make sure that everyone in the family can easily access it.
Most deadbolts are roughly standardized in size. However, always measure your door and verify that any lock you purchase will fit your door. One measurement that you may need is the backset, the distance from the edge of the door to the center of the hole the lock occupies. Another measurement is the door's thickness.
Remove the old lock by removing the screws from the indoor side of the lock. Pull the inside and outside pieces away from the door. Now remove the screws securing the bolt in the edge of the door. Slide the bolt mechanism out. The new dead bolt lock should install in a similar manner. Install the bolt, cylinder and thumb plate, by first installing the bolt then the exterior section in place. When doing this, make sure the writing is upright. Then put the interior half in place, joining the two and aligning the screw holes. Anchor the deadbolt with the provided screws.
You may choose to use the old strike plate or replace it with the new one provided with the new lock. In either case, the strike plate should be secured with 2" to 3" screws. Typically the deadbolt will come with 1" screws that do not provide enough security. Were someone to kick the door, these short screws will simply splinter the wood. Longer screws will lodge in the studs framing the door and provide greater security.