My van is rusting out on the bottom sides

If it's metal and on the left side that is likely the parking brake cable. You can tie that up with wire or a nylon tie strap. It could also be a metal brake line but those are pretty stiff and not likely to bend unless a big chunk of ice got stuck to it. You can bend those back up but if it bent that easily it might be so rusted that it's going to spring a leak soon. Your mechanic can tell you exactly what the function of the part is.