Rust
I had a similar problem with a new RV I bought several years ago. It was driven from the factory in Iowa to the dealer in North Carolina during winter. The salt from roads during that trip caked the bottom of the unit and it was not cleaned prior to sale. I didn't even think about that possibility. About a year later, it was so bad that the brake line rusted in two while I was driving it! Luckily I got to a repair facility safely. Dealer did nothing about it nor did the manufacturer because it was out of warranty. About all you can do is power wash underneath and I used a rust fixative. Not a perfect fix but stopped most of it.
Lesson learned, pay attention to the possibility of salt on a new unit, and if you can, buy a unit that was delivered during warm months.
__________________
|