Ok so the threads are messed up. I Don't recall but I think there is a threaded nutsert that it threads into.They are seized in place and aren’t adjusted well. I’ve been spraying them for months.
It's been so long since I played with that stuff I forgot. I have the tool kit in my box. Usually had to install them on new tail gates that had the bolt on lip/wing thingy.Threaded rivet might be the word your looking for. Also known as a rivet nut
I think ours are M6-1.0
They are cheap on Amazon