I hope you can offer some suggestion for repairing my fender. I’m working on a 68 mustang and I’m in the block sanding phase. While blocking the top of one of the fenders I noticed a slight depression about the size of the palm of my hand, and located about 12″ back from the headlight bucket. When I push the depression up from the underside of the fender it pops out and is no longer noticeable. However, if I touch the top of the fender, even slightly, it pops back down. Other than this the fender is in great shape. Is there a way to repair this so the depression, or buckle, in the fender stays in the “up” position? I don’t want to use any type of filler because I’m afraid if the depression pops up on its own it will crack the filler. My thought is to weld a bracket on the underside of the fender to hold it up. Also this depression acts in the same manner whether the fender is on, or off, of the car.