Hi all,

My 1993 GMC has lived its entire life in a garage prior to my ownership a few years ago. Because of its past, and the way I take care of it, the body has no rust, and the paint still looks perfect. On my old 1993 GMC, the cab corners had rusted out so badly you could just barely touch the metal with your finger and nearly go through it. I'd like to avoid this issue with this '93. What preventative measures can I take to prevent this? Does anyone know what causes it to rust out here? Is it just dirt accumulation underneath that traps moisture, or something else?

 

Man, no one? Color me surprised.

 

It was explained to me by a body guy that a metal coating used in the manufacturing processes had very poor coverage on the lower portions of the body panels, like around the wheel wells on the bed, and cab corners.

Personally, I'd get in there and spray undercoating inside the rocker. That, or wait for it to rust out, replace it and have everything in that area undercoated to seal it up.

I'm assuming that moisture gets trapped in there and road salt and what not gets stuck up in there never leaves.

 

Definitely get a truck cover. It's worth it and prevents rust and aging. I have had mine for 3 years from Covers Direct and it is completely weather resistant.

 

I had terrible problems with most every vehicle I've owned with rusty rockers, cab corners & nooks & crannies. Road salt would build up. My Sierra was no exception. I had a 64 Nova that needed new fender tops every single year.

Rust coatings seemed to eventually peel or crack & moisture would get trapped. They aren't so environmentally friendly, either. (This from a guy who gets 11 mpg on a good day. I try to be good to the planet, honest!)

A long time ago, someone told me about a product called Fluid Film. It is actually lanolin. I guess they used to use it in ballast tanks of ships during World War II. I tried it on a car & it worked very well. Then, it seemed to disappear from the world. (Pre-internet days- Harder to find stuff).

I found it a couple of years ago & started using it like a mad man all over my truck. i also use it on electrical switchgear that gets road spray. The stuff works really well. If something is starting to rust, it seems to halt it. I also use it for a bunch of other uses, some sanctioned, some not. Does neat tricks.

On my Sierra, I found access holes behind the rockers & I drilled some more, coating the new drilled edge with paint. I bought an 18" extension tube with a 360 degree nozzle & shoved it in each hole to coat the insides. (Warning- Some, like my 2000, have an inner divider wall in the rocker. you have to drill that, too.) I plugged the holes with well nuts when I was done.

I have not had any rocker or cab corner rust since. I shot the frame, too.
Just an idea to try. The only downside is that removing it is difficult. Either wash it with high pressure very cold water or use a strong degreaser. The other maybe problem is that animals, like my dog, love the smell. I think it isn't poison, but I keep her away.

The parent company is Eureka Fluid Film. I get mine from Kellsport, but there are other dealers.

Please note I have no connection to the company. I just like the stuff. They are nice people, too.

 

The product you are referencing is known as Filmco by Eureka. It was developed during WW2 for marine applications and just like the best greases and fuel additives, the products come from the marine industry. Having grownup in New England where most seem to rust proof their trucks to some degree, moving to Maryland for work I was surprised to find that nobody here even seems to even think about rust proofing until its beyond repair. Just a few months ago I found a '09 Silverado 5.3 LTZ 4x4with all the bells and whistles for only $7400 (sadly the old man who owned passed away and son in law tasked to sell just wanted it gone for folding cash). Truck was in great shape save for the rear wheel wells and I could see rust starting to form along the rockers and spots beneath the bed. I had a hell of a time finding a place that even offered rustproofing/inhibiting services. After getting a +/-$850 quote from ziebarts I figured on just doing it myself and started prepping with the couple hours of daylight I had after work. By chance I was talking to my mother's boyfriend who owns a F250 about this pain in the *** and he mentioned he was bringing his truck to Filmco in Branford CT next weekend for $400. The guy offered to do both trucks for $720 so I went up for the weekend and was super happy with the results. Filmco remains wet and tacky but won't wash off with an undercarriage wash (no moisture gets trapped and it easily gets into all those spots between doors / cab corners .They also offered to do it in the black finish or clear finish, because of the condition of the truck I went with the black while the newer F250 got the clear. All brake/fuel lines are protected and they even gave me a can for touch ups. They recommend getting it re-done every 2 years which is fine, I can get two treatments for half the price ziebarts quoted which is highway robbery in my opinion. For anyone buying a '13 or older Silverado/Sierra, aside from disabling the AFM treating your undercarriage with filmco is the first thing I would do. Best of luck.

 

A local seems to never have any rusties. He said simply remove the taillights, spray used engine oil from your oil changes into the bed walls with a pump up garden sprayer. He uses the same process all around and in the cab. Must work, his '95 that sits outside all the time isnt rusty anywhere.

PJH