The fender bolts might loosen a little, but not nearly as much as the pop-rivets that hold the carpeted inner bunk in place. The inner bunk helps provide structural stiffness to the fender. So, if the pop-rivets have loosened, replace them with bolts, fender washers and nuts...preferably brass, so they won't rust. I had to do this on both of my rangers. When the pop-rivets got loose, you could see the fenders flex on a bumpy road.