replacing the pella proline sliding door locking mechanism.

I'm afraid I'm not totally familiar with this type of hardware. Can I see a few pictures of what you have? This will allow us to research a solution for you.

Thank you for your patience in this matter. To replace this hardware, first you will need to remove both the handle and lock housing cover. To remove the lock housing cover. The cover is attached to the panel stile with several screws. The screws are driven below flush to avert interference with the lock housing cover. All of these screws must be removed in order to free the housing from the lock stile.

Once that's off, the screws for the mortise should be exposed. Simply remove the four screws holding the assembly in place and it should come right out. To install the new one, just reverse the process.

It is possible that there is a trim covering the screws in certain instances. When it comes to Pella hardware, they do not want to make it easy for you. They would rather you simply replace the door entirely, or send out for a service person to come and do it for you. We don't believe in this, of course, and we try our best to find ways around it, but in some cases it may be unavoidable.

I've never personally dealt with this trim piece, but I've seen it from other customers a few times in the past. From what I've been told, you have to pry that tab off at the top and bottom near the opening. But to be honest I'm not 100% sure. I would recommend contacting Pella directly for assistance. Knowing their company, there's always a catch. You don't want to accidentally break it because there's no telling if they'll supply you with a new one. Better safe than sorry.