One of my trimmer racks keeps coming loose on the wall of my enclosed trailer. I attached them with self tapping bolts to the steel frame of my trailer however with all the bumps and commercial use the screws keep backing out. I have the thin white walls in my trailer and can't add any 2x4's to bolt the racks too otherwise racks would stick out too far and mowers wont fit (narrow 7x14 trailer) any Ideas? I'm about to weld the things to the wall! The left side rack is the one giving me problems.