Replacing a damaged or old lock in a sliding patio door is a moderately easy home project you can do yourself. Learn how to replace the lock in a sliding patio door following a few simple steps.
Find the name of the manufacturer and model number on the sliding door and use this information to purchase a lock that will fit.
Slide the patio door all the way open.
Unscrew and remove the existing lock. The lock will have screws on the interior side of the door. The screws hold the interior and exterior pieces of the lock together. When the screws are removed, the interior and exterior pieces of the lock pull apart from the door.
Unscrew and remove the existing door strike from the door jamb. The strike is the part of the lock that the door slides into. When the door is closed, the opening in the edge of the door fits over the door strike. When the lock is turned, the lock latch slides down into the strike and locks the door.
Insert the new lock piece with the screw holes and locking mechanism into the opening on the interior side of the patio door. Insert the back of the lock into the opening on the exterior side of the patio door. Hold the two pieces in place while tightening the screws. The two pieces will line up and fit into each other as the screws are tightened. Tighten the screws until the two pieces fit securely to the door.
Screw the new door strike into the door jamb.
Slide the patio door closed and lock it. If the latch does not line up smoothly with the door strike, open the door and slightly loosen the screws in the strike. Slide the door strike up or down until the lock latches easily. When the lock latches easily, open the door and tighten the screws in the door strike.
Study how the existing lock is screwed into the door and the door jamb. This will help you put the new lock into place. If you can't find the name of the door manufacturer and model number, look carefully at the lock on the door. Take measurements or a picture of the lock and take the information to a home improvement store. A customer service representative will be able to guide you to the lock that will fit your door. If the new door strike will not tighten firmly against the door jamb, use longer screws to secure the strike to the jamb.
To avoid injury, slide the door all the way open so it will not move while you are removing and replacing the lock.