I have an ARE camper shell on my 2000 F350 and no matter how much it pull it together or tighten the clamps, within what i think is reasonable, the sides of the cover seem to spread out. There is a gap between the lip of the shell and the bed rails. Ive tried clamping it down while a racket strap is pulling the sides in tight and it looks good then but over time everything starts to separate. I haven’t replaced the double sided gasket/ foam on the bottom of the shell rails, i dont know if thats could be causing it to behave the way it is but it seems hard t believe since it has the clamps. Anyone have any ideas?