I have a 6 foot chain link fence. The end posts that come up to my house are set in concrete and do not move at the base but they still tend to wobble a bit near the top because of the height. I would like to know if filling the post up with concrete you be a good way to add more stability.
That wont solve the problem. The best way to make a 'solid' fence post is to bury more into the ground.
Putting a cement ball at the bottom is not the best solution and filling the hollow cavity will do nothing to help