The key for this lock is very rusty and old and barely works, so I want to replace the dual cylinder deadbolt lock, below the doorknob, with a new lock.
I don't see any screws on the deadbolt lock, and I tried to pry off the plate on the front of the lock, but it doesn't seem to work. How can I remove it so I can put a new one in?
Edit: new image:
The knob removes by loosening the visible screws.
The lock cylinders are threaded into the lock body and secured by setscrews accessable from the edge of the door, located level with the center of the cylinder. Loosen those a few turns, then rotate the cylinders counterclockwise to unscrew them. Depending on what kind of protective ring the cylinders have around them and how stiff the connection is, it may help to insert a key blank and use that as a thumb turn to rotate the cylinder -- don't force it, and don't use any key that has deep cuts or that you would mind damaging, as warping and breakage are possible.
It is then possible to remove the lock body from the door, if desired. I'd do a basic inspect/clean/repair while I had the opportunity, but I know what I'd be looking for.
To reassemble, reverse these steps. The setscrews engage with the grooves in the cylinders to keep them from being unscrewed by anyone else.
