You may need to remove a door lock to do a lock repair, or to adjust a door latch. Unless you have a high security or commercial lock installed by a professional locksmith, you should be able to remove most household locks with ease.
Parts of a Door Lock
Plug or cylinder: Part where the key goes, or the "guts" of the lock.
Casing or cap: Decorative covering that goes over the working parts of the lock.
Through bolts or casing screws: Two long bolts that hold the halves of the lock together.
Striker plate: The plate in the doorframe that receives the latch or deadbolt of the lock.
Latch: The part of the lock that goes into the striker plate.
Deadbolt: A bar or bolt that goes into the striker plate of the door to secure or lock it.
Step 1 - Remove the Latch Plate
The latch plate is a small piece of metal held in place on the edge of the door by two screws. Remove it using a screwdriver.
Step 2 - Remove the Casing Bolts
The casing is the decorative and functional cap covering the guts of the lock. It is held in place by two bolts or screws on the inside of your exterior doors. The two long bolts hold the casing and the halves of the lock together. Using your screwdriver, unscrew the bolts while holding the backside of the lock, so it doesn't fall off once the bolts are removed. In some decorative locks, there may be a side latch on the edge of the casing that must be depressed to release the casing and to see the casing bolts. If no bolts are visible, look on the side of the casing for an alternative release.
Step 3 - Pull the Lock Out
Once your latch plate is off and your casing bolts are removed, pull the two halves of the lock straight out on each side of the door. You'll see the frame of the lock that holds the latch or deadbolt plug remaining in the hole. You don't need to remove that unless you are changing out your entire door lock. That part is removed by pulling it out from the edge of the door where you removed the latch plate. Your new lock may or may not fit in the hole left by removing the old lock.
Replacing the new lock is simply a matter of reversing the process, and is sometimes a little more difficult to do. Noticing how the old lock comes apart and making sure you seat the bolts in the holes when replacing the lock will make the replacement easier. Don't over tighten the casing bolts when doing a replacement to avoid seizing up the lock.