Smoky,
Motorhome manufacturers have only begun addressing the problem of chassis rust in the last couple of years by treating the frame before assembly.? Before that they would spray a cheap black paint that in most cases did not have anti rust or anti corrosive properties.?
Since buying our 1998 American Dream, I have always kept a quart of a top quality, proven rust inhibiting paint on board, and whenever I am under the coach performing routine maintenance apply a coat of paint to the frame or touch up portions where the paint may have come off.
Not all paint containing the word "anti rust" are rust inhibitors, so choose a proven product.
Exposure to road salt and or grave roads will exacerbate the problem....we have all see the effects of road salt on coaches used by snowbirds who travel from the north in the middle of winter.
Rust can be a serious problem and should be treated pro actively...unless you coach is a recent model in which the chassis has received treatment.
Dealer applied undercoating is a waste of money and does not prevent rust
