The other day I noticed that the large screw that holds the back section of the tower together was loose.. the screw that you take out to lower the tower. I tightened it up and all was fine. Then today, It fell out while we were wakeboarding.. I went to put it back in and found that it was totally stripped out. I never put the tower down, so I'm not sure how this happened.

What is the best way to fix it? Can I just fill the hole with something like JBweld and re-tap it? is there a better way? I havent ever done much work with aluminimum so i'm not sure what is best.