patio door lock not working

A home owner from NJ says:
My patio door won't lock. It's very stiff when you try to throw the latch. I've taken it apart. I have a keyed handle set. I've tried using a screwdriver to move the lock up and down and it will come out but only with force. Do I only need a new mortise? Does it look like 82-218? Does my handle set still look good? And finally, when I go to put the handles back on, how do I align the "posts" on the lock and switch sides into the mortise opening?
I am a "mom" trying to fix this, so details please!
Thumbnail of the uploaded file named Door Mortise.jpg
Thumbnail of the uploaded file named Door Handle Set.jpg
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Tom from SWISCO responded:

Hello! Your handle set looks like it's in good condition, and based on your screwdriver test I think it's a safe bet that you only need a new mortise. I definitely recommend our 82-218. Now, when you try to install this in your door, it may seem like it's too big, but you just have to put it in at an angle to get it to fit. The video below will explain how this is done. It will also how to explain how to pop it in without it falling into the door on accident, which is an unfortunate design flaw with this particular mortise.

As for aligning the key tail and thumb lever with the slot, you just have to turn them until they fit. The slot on the 82-218 is always at a 45 degree angle when the hook is retracted, if that helps. This other video may actually be of use to you on that front, too.
I'm happy to answer any other questions you may have on this project. And don't worry, you really did your homework. You've already gone further on your own than a lot of contractors I talk to every day, so you're on the right track.
How to install a Legacy Handle Set
How to install a Legacy Handle Set
VIDEO
WATCH >
How to install the 82-218 Mortise Lock
How to install the 82-218 Mortise Lock
VIDEO
WATCH >
How to maintain a sliding glass door
How to maintain a sliding glass door
GUIDE
READ >
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