The problem is, after 13 years of camping the vertical piano hinge for the trailer doors is wearing. I noticed it because the door didn't want to shut, it was dragging at the bottom. And very difficult to close.
After first checking for obstructions, and screws that may have worked themselves out and become obstacles. I continued looking and discovered that the aluminum piano hinge now has a lot of slop in it such that I can lift the trailer door up about an eighth of an inch or so because the hinges have worn, sort of like the way that a chain wears. So there are gaps in between each segment of piano hinge now.
I came up with an interesting fix, very very simple but it's working. What I did is insert a piece of wire through the hinge and bring it back so that it is a spacer and will not allow the door to drop down anymore. The wire I used was some kind of loop hook, I don't know what it was for maybe a very small curtain or something.
Anyway you can see in the picture what I'm talking about; that wire sticking out used to be a loop hook and now it is a hinge shim. I just bent it down and left it long in case I need to modify it in the very near future.
I'm quite pleased that the door closes easily now. :-)