2008 F150 - rust prevention
 

So, we inherited a 2008 F150 that has 64k miles. It rust free but used as a truck to the bed is a little beat up. My question: This truck came from SoCal and is rust free and it now lives in SW WI and every truck here seems to rust above the rear wheels in the wheel well. Is there a way to prevent this that isn't horribly expensive?

That's from rocks chipping the paint. Exposed metal = rust. Faster with humid air and salted roads.

To fix... dont drive in the salt. Wash down after driving in the salt. Fluid film, or some other under coating.

Here they rust from the inside, maybe undercoating the inside of the wheel well?

As a side note, none of our vehicles have that issue, seems to be just pickup trucks.

Fluid Film seems to work pretty good around here Brent.
I've never used it in bulk just spray cans. Napa carries it.

Be sure to also coat the frame rails behind the rear wheels. That's where mine cracked.

Best
Les

my 2014 gets exposed to the salt laden roads of NYS for 6 months a year and rust is terrible here. after a few tries with cosmoline (sp) I tried POR15 and am hooked. encapsulated what I could not wire brush off and a year later looks great. chasing some wheel well rust next a few bubbles just appeared. not sure on that approach yet , but would rather have a hacked touch-up than rust.

Any welded seam is likely to rust given salt and water, keep spraying it with thin rust preventative oil. Most of those areas have access plugs, rinse out regularly with water, and give a shot of oil, if dirt builds up the trapped moisture will make it rust from the inside.

The best job I have seen around here comes from a place that uses a used motor oil film concoction .
Whatever product you use, I think you want something that never hardens and is always running down into all the nooks and crannies .
Honestly, out of all the rusty vehicles I see here, the ones treated like this seem to hold up the best .
There is a new shop here, and I believe he is using something similar to fluid film . It also stays pretty wet, months after it is applied . Too new to see how well it holds up , but it looks like he does a good job . Prep is key . Also helps to know what ares hold salt and grime, and are rust prone .
Sucks that things do not last here, the only way is to not drive from November to April .

We have a 2000 Durango that only has one front quarter panel rusted and that is the one replaced after a meeting with a herd of deer one evening. There are a few other areas of surface rust I try to keep at bay with rust converter, primer and paint and those are seams in teh bottoms of the doors.

With this truck being from the desert of CA I thought we could prep and it sounds like there are a few options.

Fluid Film ...check the videos testing a variety of products

yup

I have a 2007 Siverado with rust starting above the rear wheel wells like they all seem too do. I plan on treating the surface rust with a rust inhibitor then installing OEM fender flares. Kind of like lipstick on a pig but good enough for the age of truck.

+1 for fluid film. My 94 S10 was rust free until this spring. A paint bubble popped up on the rocker panel. Within 3 weeks it was 3 paint bubbles. I sanded them down and found the rust was coming from the inside of the rockers. Poked through and had 3 holes, 1/8" by 3/8". Filled and painted and went in through the back side with fluid film spraying both rockers. It has been 5 months and no new paint bubbles. The first ones spread so fast, I am convinced the fluid film stopped it.

Just to bring this back up, I took the truck to get a quote on a spray on bed liner. While there he suggested a product new to them called FinalCoat. They do the fluid film and hard undercoating as well, but said they have better luck with these. $650 installed though. Sounds iffy, but I know they use them on metal hull ships with great success.

$650 doesn't seem bad if they're prepping the underbody properly before spraying with the coating.

A rust conversion/seal before top coating might be prudent.
Ospho Rust Treatment - Since 1947
https://www.magnetpaints.com/underbody.asp

I used:
https://www.eastwood.com/ew-rust-converter-new-formula-aerosol.html (worked it in with chip brush)
https://www.eastwood.com/eastwood-rust-encapsulator-aerosol-red-15-oz.html (didnt work well sprayed and stayed on surface)
https://www.eastwood.com/eastwood-extreme-chassis-black-primer-set.html (no long-term data)
https://www.eastwood.com/eastwood-internal-frame-coating-14oz-aerosol.html (bottle went very fast and covered little but nice tube applicator)
Eastwood was quite expensive $500ish) and I wasn't entirely thrilled with some of them, but there was probably user error involved.

Undercoat the large panels and use the specialty products for the frame and smaller sections.
Use FluidFilm or make your own WaxOyl for the small bits.

A truck will be easy to DYI in good weather after power washing .

I get my vehicle sprayed every year. I have to park it on the street for a week so most of the excess product seeps out. Maybe there's a company where you are that does a spray for rust prevention.
My last vehicle was an 06 Tahoe, there was just surface rust on the frame when I traded it in earlier this year.

I have been using the NH oil coating for a few seasons .

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Your cars don't typically rust through there because there is a plastic wheel well liner that keeps road crap out of the flange. Truck beds don't have a liner and the salty road crap gets sprayed everywhere inside the fender cavity and collects and hangs out there. Aside from a spray treatment, hosing it out regularly will do a lot to keep it from rusting there.