Although they may seem complex, garage door locks are quite simple to replace. Garage door locks have lock bars that attach to the lock to secure the garage door. When changing a garage lock, you can reuse the existing lock bars. Garage door locks are available at home improvement centres and garage door dealers. It is a good idea to replace the lock with the same type currently on the door. This will prevent having to cut new holes into the door. The door must be closed to replace the lock, so a helper is necessary to work outside.
Close the garage door. Go to one side of the door, and pull down to seat the door fully to the floor. Lock the jaws of a pair of vice grips on the track over the third roller from the floor. This keeps the door down while you are changing the lock.
Remove the screws securing the lock bar guides to the garage door with a nut driver. The lock bar guides are the metal pieces at each end of the door section that the lock bars ride through. The ends of the lock bars will fall down to the floor.
Locate the screws securing the inside portion of the lock to the garage door. Remove the screws with a Phillips-head screwdriver. Have a helper hold a flathead screwdriver on the upper retaining screw on the outside portion of the door lock. Remove the upper retaining nut on the inside of the door with a nut driver. Repeat for the lower retaining nut and screw. Pull the inner door lock away from the door, and have your helper pull the outer door lock away from the door.
Loosen and remove the bolts securing the lock rods to the inner lock assembly. Ask your helper to insert the new outer lock assembly into the door with the handle pointing to the side. Ensure that the inner door lock assembly is in the unlock position. There is a slide that goes from side to side. One side of the slide has a hole, and the other side is bent. The bent side of the slide should be further away from the mechanism than the hole. Press the release tab on the top of the mechanism to ensure the lock is in the unlock position.
Ask you helper to insert the upper threaded bolt through the outer door lock and into the door. Position the inner door lock against the inside of the door, inserting the end of the threaded bolt through the top edge of the lock. Thread a securing nut over the bolt until hand tight. Have your helper insert the lower threaded bolts through the lock and door. Manoeuvre the inside lock as necessary to insert the bottom bolt through the bottom edge of the lock. Thread a securing nut over the bolt until hand tight.
Install two securing screws into the inner door lock to secure the lock assembly to the door. Tighten the two retaining nuts with a nut driver. Push the bent side of the lock slide toward the opposite side of the door. The door lock slide should move freely until you here a pop indicating it is in the lock position. Press the release tab on the top of the lock, and the slide should snap back quickly. Have your helper turn the outside handle to lock the door from the outside and unlock the door lock with the key. The slide will operate the same way. If the slide seems tight, loosen the securing screws in small increments until the slide moves freely.
Place the garage door lock into the locked position. Place a lock bar guide on each lock bar. Insert one end of the shorter lock bar into the square hole on the right-side track. Place the hole on the other end of the lock rod over the hole on the lock slide. Secure the lock bar to the slide with a retaining bolt and nut.
Insert the end of the longer lock rod into the square hole on the left-side track. Position the hole on the other end of the lock rod on the tab at the bottom of the inner lock assembly. Secure the lock bar to the tab with a retaining bolt and nut.
Position the lock bar guide straight on the end of each side of the garage door. The lock bar guides should be two inches from the end of the door. Lift the guides until the top of the lock bar touches the top of the square hole on the track. Lower the guide slightly, and secure the guides to the door with the retaining screws. Remove the vice grips from the door track.