(Continued. Evidently there's a 1,000 character limit on profile comments.)

If that doesn't work, it might be worth hitting the latch area with a torch to hear things up, expand the metal, and hopefully loosen things up. It might be difficult to get heat exactly where you need it in this situation though. The heat will definitely burn up the paint in the area where it's applied also, so I'd use that as a last resort.

If all else fails, and you have to cut a hole to access the latch assembly, I would cut the hole in the side of the box, not the door. It's out of sight and could easily be patch up with a piece of sheet metal, some silicone, and some screws.

Good luck, and let me know how it turns out!

Sorry to hear about that, but I'm glad you were able to get the rest of them open!

Is the hole where the handle assembly was mounted big enough to get your hand and arm inside the box? If so, I'd try sticking a can of penetrating oil inside there and hosing down the latch assembly.

Whether you can get oil on it or not, I'd try pulling on the cable with a bar before I cut into the door or box. Loop the cable around a pry bar in such a way that the cable overlaps itself and holds itself still when you pull on it. Position the bar such that you're able to use the edge of the handle hole as a fulcrum to put tension on the cable directly away from the latch. Cut a piece of wood or angle iron or something to put between the sheet metal and the bar in order to spread the force of the bar over as much of the edge of the metal as possible and hopefully avoid denting or bending the sheet metal.

Hey John! I wanted to ask your opinion--I am working on trying to get into my cargo boxes. I have all but one of them open-the one that was too rusty. I ground off the rivets and pulled the handle assembly out. I cut it loose from the cable that goes to the latches on the sides. One of the latches opens fine, but the other one is rusted in place. I had this same problem in one of the other boxes, but it was one of the boxes that's divided in half, and I was able to crawl inside and unscrew the latch. When I looked at the latch, there was so much rust built up on the "bolt" part of the latch that it couldn't slide in the "housing channel" part of the latch.

This box is a single large box, and there's no way I can access the back of the latch. I'm REALLY loathe to destroy the door, but I'm not sure there's any other way to get the box open.

Any bright ideas?