Lock cylinder

Thanks for your patience during this busy season. To be honest, this mortise lock is actually unfamiliar to me; I've never seen it before. I'm going to consult with one of my senior colleagues who specializes in patio door hardware; he may have a better idea, and we'll get back to you as soon as we can. 

Perhaps I can be of assistance! Your handle looks similar to the 82-402. This has a 'knockout' key hole in the exterior handle and can take the 82-310 key lock. Now, I don't see the indentation for such a key lock on the exterior handle in your photos. Instead of replacing the entire handle set, you could try and just replace the exterior pull with our 82-306 keyed pull. See if the mounting holes and key plug match up to the one in your door. Let us know what you find.

You know, looking at the inside of your pull, I see you might be better off just trying to see if our 82-315 Key Lock & Housing would work with your existing hardware. To install, you would need to punch out the center knockout hole; you'd then need to see if the smaller 'divot' holes align with the mounting holes on the key lock, which are 1-7/8" apart, as you'll need to drill through the divot holes to install the housing. See the diagram below:

Dimensions for 82-315

Also see the video below about installation of the 82-315 on a similar outside pull:

Now, I stress that I can't be entirely sure this will work; it's possible the key-tail will not be compatible with your old mortise lock. But I think it's the best solution we have. The components of the 82-402 are not sold separately, so this certainly would be a more optimal solution if you can get it to work. The 82-315 comes in bronze as well as white and beige. Let me know what you think.