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How can I prevent body rust?


05MDLJ

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I've been able to read up plenty about how to handle and prevent frame rust on my LJ. With that, I want to do the same for the body. I know the issue with the fender (already rusted out on my Jeep). What about the other common spots like below the doors and below the taillights? Any ways to prevent these spots? Anything else folks have done to preserve a good condition LJ body?
 
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Juggernaut

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3M makes a product called cavity wax that is good for applying to the back side of panels or between panel skins. With a wand or straw applicator you can access the from below the taillights, in the torque boxes, doors, etc.....
 
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05MDLJ

05MDLJ

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Where does the rust under the door come from? I haven't looked specifically for potential causes but can't picture it.
 

Juggernaut

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I don’t have that issue but I religiously clean the mud from under the rocker panels. I could see this contributing to rust. Also there is a seam where the floor pan welds into the tub. There’s seam sealer at this location but moisture within the seam will cause it to rust from the inside out over time. Similar to rear tub corners.
 

TJ4Jim

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Where does the rust under the door come from? I haven't looked specifically for potential causes but can't picture it.
In snow /ice conditions where salt is used the front and rear tires distribute the mixture very nicely to all areas. Ignore that long enough on our Jeeps and rust will inside out starting from under the tail lights, door rockers, windshield frame and top of the front fenders.
 

AjRagno

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Fluid Film.

Your Jeep will rust wherever unpainted metal is exposed to both water and oxygen.

After daily driving though 8 Minnesota winters my ‘05 LJ is still entirely rust free.

You probably need at least 6 cans the first application. Spray it on the entire underside, including inside the frame (essentially everything except the exhaust and brakes).

For the front fenders, make sure you look for any seams, creases and holes and saturate everything. You also want to pull down the rear wheel well liners and spray the inside of the tub down from the taillights.

After the first snow/salt event crawl underneath and re-spray wherever you see salt residue.
 

PCO6

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Reviving this semi-old thread. I'm repairing parts of the the body on my year round use LJ and am painting the whole vehicle. Here are a few things I've done to avoid future rust problems. There have been and will be more.

Front fender rust was mentioned above. The problem is the support panel that is located under the flat top of the fender. I bought replacement fenders and I could tell that they were barely painted between the two sheets of metal. The original stock fenders were better but they eventually rust out too. There is no way that you can apply rust protection in this area. I question how much support the panel provides so I just cut them out. I've since painted the fenders and I don't anticipate any problems.

I also replaced the windshield and frame. I was able to inject Fluid Film in the top of the frame and down the sides from the interior. The holes for the top frame and hard top clips is a good spot. There is no way to get to the inside of the bottom of the frame though. This is really the only part of the frame that is a rust spot and it's bad. A little unusual but I drilled two 3/8" holes through the frame just behind the windshield wipers. They're visible but partly hidden by the wiper arms. They don't jump out at you and with a dark Jeep they would barely be seen at all.

Always curious to see what others are doing!

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Fluid Film 360° Extension Wand for spray cans by Fluid Film: Amazon.ca: Home & Kitchen
 
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tr21triton

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you all that swear by fluid film need to look at cor-ban 35, it's the cats ass for corrosion prevention.being a aircraft mechanic, i've used it all. the thing with fluid film is it doesn't really dry, and doesn't last when exposed to the elements. cor-ban will dry in a few hrs to a hard coating, that can be seen through and will last a long time. only thing that will remove it is MEK and SKYDROL (aircraft hydraulic fluid, bad shit that will eat the paint off anything and burn the shit out of skin) pressure washing wont touch it (try pressure washing fluid film). if it gets scratched off you just reapply it. you just spray a few thin coats on a surface and your done. if you use it please wear atleast a dust mask and long sleeves, because it sprays in a fine mist and sticks to everything. i have seen it at HOME DEPOT i believe.
 
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PCO6

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you all that swear by fluid film need to look at cor-ban 35, it's the cats ass for corrosion prevention.being a aircraft mechanic, i've used it all. the thing with fluid film is it doesn't really dry, and doesn't last when exposed to the elements. cor-ban will dry in a few hrs to a hard coating, that can be seen through and will last a long time. only thing that will remove it is MEK and SKYDROL (aircraft hydraulic fluid, bad shit that will eat the paint off anything and burn the shit out of skin) pressure washing wont touch it (try pressure washing fluid film). if it gets scratched off you just reapply it. you just spray a few thin coats on a surface and your done. if you use it please wear atleast a dust mask and long sleeves, because it sprays in a fine mist and sticks to everything. i have seen it at HOME DEPOT i believe.

Sounds like a good product. I'm guessing that you'd have to have a good painted surface on the underside for it to stick to. I can see it being very good for hardware and a lot of areas under the hood.

I've never had a problem with the "fluidity" of Fluid Film or Krown T40 which are the only products that I've used. I see what you mean on external flat surfaces (underside of floor, etc.) but they're great in closed areas like frames. I tend to pressure wash a lot of exposed areas off in the Spring and reapply it in the Fall.
 
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PCO6

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Salt water has proven your theory wrong.

You may be right. Years ago I bought a '69 MGC/GT (fairly rare) that spent most of its life in Florida, although I'm not sure exactly where. It was as bad as many cars I've seen here about 50 miles north of Toronto.

If you take care of them almost anything will last. I have an '88 MJ and an '89 XJ that are rust free and they've never been out of Ontario. The previous owners were good with them.
 

tr21triton

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cor-ban will be even better for inside the frame. they have a spray nozzle extension and you can just fog the inside, but you would need to get all the fluid film out 1st which would be a PIA.
 

TWiG01

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I also like fluid film. Easy to apply and reapply and I like how if you want to remove it you can, easily. The aircraft sealant sounds like some quality stuff, but also a pain in the ass if you want it off.
 

TheBoogieman

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you all that swear by fluid film need to look at cor-ban 35, it's the cats ass for corrosion prevention.being a aircraft mechanic, i've used it all.
Do aircrafts regularly see mud?
p.s. Have you seen what comes out of a cat's ass? It's not an Eastwood product. Fur balls and shit. You need to use better analogies.
 
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tr21triton

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Do aircrafts regularly see mud?
p.s. Have you seen what comes out of a cat's ass? It's not an Eastwood product. Fur balls and shit. You need to use better analogies.
no just 500mph rain, sleet and salt water humidity that can almost act as a sand blaster. mud will have no affect on it, just pressure wash it right off, no need to reapply
 

Goatman

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That Krown product is the absolute worst rust preventer I have ever seen. I think WD-40 is actually better. Seriously. Sure is pricey tho. For ease of use the fluid Film is hard to beat. Too bad there isn't some product that is inbetween fluid Film and all the Cosmoline/ frame wax products that dosen't wash off as easy as FF but not as nearly permanent as the Cosmoline type products.
As for the fenders rusting out, if you take a grinder and cut a line across that wavy bracket underneath you can get any moisture out, then spray in your choice of rust stop product. Give it a week or so to remove any possible moisture then seal the grinder cut with a good silicone product. I've heard good results from this. I did it to my TJ last year to stop rust that just kept coming thru the top of the fender no matter what I did.
 

Juggernaut

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That Krown product is the absolute worst rust preventer I have ever seen. I think WD-40 is actually better. Seriously. Sure is pricey tho. For ease of use the fluid Film is hard to beat. Too bad there isn't some product that is inbetween fluid Film and all the Cosmoline/ frame wax products that dosen't wash off as easy as FF but not as nearly permanent as the Cosmoline type products.
As for the fenders rusting out, if you take a grinder and cut a line across that wavy bracket underneath you can get any moisture out, then spray in your choice of rust stop product. Give it a week or so to remove any possible moisture then seal the grinder cut with a good silicone product. I've heard good results from this. I did it to my TJ last year to stop rust that just kept coming thru the top of the fender no matter what I did.
The 3M cavity wax maybe similar to what your looking for. Higher viscosity than Fluid Film. It doesn't harden so its self healing but does dries to a thicker film like a cosmoline. More comparable to the wax coating GM uses ( used to use?) on its frames. Most autobody shops around here use this product or comparable for oem collision repairs.

Also for fun google Project Farm channel on Youtube. He does a comparo of rust inhibitors and other products that's somewhat methodical and at least entertaining.