Have 2000 ranger xlt....do to rust issue...replaced gas filler neck...gas tank straps...rear shackles....rear shock supports....rear cross member frames...complete rust out on tire holder...50% of rear frame rust out repair...rocker panels rotted where the dirt can't be washed out....to me most of the rust occurred where the dirt couldn't come out do to design....step up ford...and do the right thing.....recalls!!!!

 

2 words

good luck

15 year old vehicle..nothing you can really do at this point

 

Rust happens when oxygen comes in contact with metal, rust is oxidation of metal, so not sure how you could blame Ford specifically for building trucks out of metal or for our oxygen atmosphere.

Paint helps to keep oxygen from contacting metal parts but it often wears off, especially on the under side of vehicles, so needs to be redone, any coating that keeps the oxygen off helps.
Liquids like water have oxygen "built-in, i.e. H2O, and can increase rusting process, minerals(dirt) is "salts", and mixing water with the "salts" really speeds things up.

Once rusting starts it is self promoting, it makes it's own "salts".
You can stop it by using Phosphoric acid, Naval Jelly has this as does Coca Cola(not as much, lol)
Phosphoric acid actually changes the rust into a coating that protects the metal underneath, but you need to get all the rust or it will startup again.

Painting over rust will slow it down, but won't stop it.