Hi L. I have a 93 Bigfoot
13.5'. Take a framing square and check the opening. Mine is out of square from manufacture.
The door was square. I can measure the door opening no mater how the trailer is positioned, and it is out of square just the same. The frame was not set square when it was attached to the body.
Is there a skid block on the threshold on the strike side ? mine had one; from the factory. As the door closed it would lift the strike side of the door 6+-mm up. (1/4") allowing the door lock to engage with the strike plate.
I took the door off the hinges and took it apart. It is screwed together. I found the wooden core at the bottom rail and up the stiles rotten. wet like a sponge.
I worked as a house cabinet maker. ( retired ) I have made many kinds of wood entrance doors. I made new wood interior parts for the trailer door.I drilled holes in the bottom aluminum rail, of the trailer door to let the water that came into the core escape
. Drill outside edge.
I recut the mitered corners of the aluminum door frame. the corners are no longer 45 degrees. I had a pattern of the opening, I cut each corner out of square to fit the pattern. under 45 a little over 45, a little bit.
The door does not need the skid at the bottom. I adjusted the strike plate a bit.
If I cut each corner 3 mm out of whack it can work very nice.
I recut the screen door the same way.
Nothing rubs or hangs up. Even if the trailers if parked out of level.(square).
A miter chop saw with a carbide blade will cut the aluminum.
If you were to have a cabinet maker rebuild the door use a pattern.