The mortise lock for our sliding glass door to the deck broke. Luckily, we did not have to replace the entire door. Here’s the instruction video I followed. When unscrew the lock, make sure you put the screwdriver at the bottom of the lock to secure it rather than the top, which showed in the video. When I placed the screwdriver at the top, the lock dropped. It’s a pain to take it out. The mortise lock cost $13 at Home Depot.