Apparently I exceeded the weight limit of my tool chest which caused the bottom panel to bend. The casters just bolt into the sheet metal with a thin reinforcement piece riveted internally. I pounded them out once before, but the weakened sheet metal just bent again. To repair it, I picked up some scrap 3/8″ steel plate and match drilled it to the base. I then bolted the casters through the plate to the case. I don’t think I’ll have any issues with this anymore.
I moved the tool chest into the corner. The floor here isn’t close to level, so I put some pieces of scrap 1/2″ thick steel plate under the front wheels and reinstalled all of the drawers.