Hey, i live in southern ontario, and they spread salt like crazy here, i just got my 97 f250, and i was wondering what the best way to protect my truck from rust would be? I just pressure washer it really good, and i am going to cover it in undercoating oil! but i was wondering if there is anything else i could do? My parents truck has the 7.3L and it almost has 700,000 kms, but now the body is starting to fall apart, i wanna be able to get as many kms out of my truck as possible, and keep it looking good too.

 

The two body spots that often get rust are the areas around the wheel wells. Water seems to build up in there. My rear wheel wells are rusting out right where the chrome molding is above the weather seal. Almost rusted through. So you might look to coating those areas really good and seeing if there is anything you can do to get it to drain better. My front wheel wells are rusting at the back of the wheel well down at the bottom. Again, looks like a drainage issue to me.
The other spot is the bottom of the doors. They don't drain well and so if you look from inside up where the window water drains, those slots never reach all the way down to the seem and so water collects and stays in there. I have meant to use my dremeal and cut those deeper so there isn't a groove and then spray rust converter in there and hope for the best. Haven't gotten to it yet, though.

 

I think the best way to fight the rust is paint, but it's also the most work. I hope to paint the soft white underbelly of mine this summer and then stay on top of the cleaning (pressure washing) and keep it oiled intermittently. One thing I will say is that if you intend to do paint at any time, don't oil it until you are done with the paint. Once you spray that oil on there you will have one nightmare of a job on your hands getting it clean enough for paint to stick.

Dan is right on with those two hotspots. The third would be the location of the bottom bolts in the core support. There are "cups" or sort there that collect dirt, grime, salt, and water and that stuff is relentless in rusting away your beloved ride. IN fact I think the majority of the trouble in all three of those spots is not so much that they hold water as it is that they hold dirt, salt and road grime, which holds moisture and never really dries out. The solution for the rear wheel wells is pretty well documented and invovles making some holes in the inner fender support to allow that crud to drain out. Diesel Brad did a nice writeup on what that process looks like, but it's not for the faint of heart and involves body work. You can also rinse it out with a hose fairly well, but the holes will make for a more "passive solution" as opposed to rinsing the crud out which requires you "actively" getting in there with a hose.

I'm right there with you on having a fairly rust-free specimen (at this point) and wanting to keep it that way. What I intend to do is some real in-depth cleaning, then using a rust treatment pain like POR15 on the undercarriage to seal everything up and then top coating it with some enamel paint. After that I guess we'll see what happens, but I have a feeling I'll end up using some oil or fluid film or something in certain places to ease my mind. There's got to be a way to keep these things from rusting apart. I'm about to bring the WAR!

 

Volkswagon uses some form of a wax or something for inside of there body panels. An auto body guy informed me of it when he re-did his truck. Apparently it is one of the better rust protection products out there which would explain why the only ones around here that are rusted out have a ton of miles on them and at least 15 years old.

 

The CRITICAL (i.e. relevant to safe operation) rust-prone areas are:
* Radiator support, at the two forward cab/frame mounts
* Spring hangers/shackles
* Outboard base of cab, where the seat belts mount

 

Thanks for all of the info so far, i didnt know about the wax like rust protector. What about if i got a body/paint job, and then used a line-x type coating over the in side of the body (ie: wheel wells, bumpers, frame, etc)? Whats the best oil for under coating? Krown? Fluid film?
Does anyone know what audi does to there cars, because they have a ten year rust warranty?
Thanks again

 

There's a dirt trap at the bottom inside of the rear quarter panels, below and a little bit forward of the rear stake pockets. Mine collected a bunch of crud there, and rusted through. Get the pressure washer pointed up and outboard from behind the quarter panels.

An issue with any heavy solid film is that if water ever gets behind the film, the film holds it there and the steel will rust behind the film. I would be really hesitant to use Line-X or anything similar except in a factory prior to assembly.

The wax and oils are "slushing" oils... soft, but still exclude oxygen and water. Since they're soft, they don't peel or crack and hold water against the metal. You can just wipe them around onto any bare metal.
When I replaced my bed, I powerwashed the frame and spray-bombed with Rustoleum before putting the aluminum flatbed on. I was tempted to try a mix of boiled linseed oil (stays tacky and soft) and black Rustoleum, but didn't have a decent spray and the spray cans are far easier... especially with one of the inexpensive can-holder-squeeze-trigger gizmos.

Periodic washing to flush out gunk seems to be a good way to help longevity, no matter what coating is on the metal.

 

I'll state the obvious, but only true method of protection: Get a seperate winter vehicle.
No matter what you do, if you drive your truck in the salt/winter, it WILL rust through. My '96 hasn't seen the winter roads since 2001 and both rear wheel wells are rotted through. The rest of the truck is spotless, and believe me, I took as good of care of the truck as possible when I bought it brand new. There's simply nothing you can do except not drive it in the winter. At all. Ever.

If your parents truck has driven 400,000 miles through the same winter/salt as what you will see, and is only now starting to fall apart, then I'd say you have no idea what salt really is.

 

Pshhhhh...I have a much better and more obviuos solution! Move south! No winter issues and better bbq! Lol

 

Or move East.
I went to PA a couple weeks ago. The next day I thought I was walking on the beach in my garage.