All the rust I'm dealing with right now is on the undercarriage. Suspension parts and drivetrain are quite rusty. I'm not too worried since they have plenty of steel to last a long time. Will deal with that stuff later. The sheet metal is a different story. Need to get the jump on this before it gets too bad. Here's some photos of what I'm dealing with.

 

Over the years I've tried a lot of paints to no avail. No paint will stop rust when the rust comes from inside the body panels. I've done a ton of reading and narrowed my choices down to POR15 and Chassis Saver. They are supposed to stop moisture from getting through the paint which keeps the rust active. I bought some Chassis Saver and did one vehicle with it a couple years ago. Took it down to bare metal. Within 6 months the rust was back in some areas and causing the paint to bubble. Even though it looked like I had bare metal, it was slightly discolored, indicating that the rust had already started coming through from the inside of the sheet metal. Anywhere I had good metal the Chassis Saver seems to have held up well. Seems pretty tough so that's what I plan to use on this project. Any other ideas, experiences and suggestions are welcome.

 

No paint will stop rust when the rust comes from inside the body panels. I've done a ton of reading and narrowed my choices down to POR15 and Chassis Saver. They are supposed to stop moisture from getting through the paint which keeps the rust active. I bought some Chassis Saver and did one vehicle with it a couple years ago. Took it down to bare metal. Within 6 months the rust was back in some areas and causing the paint to bubble. Even though it looked like I had bare metal, it was slightly discolored, indicating that the rust had already started coming through from the inside of the sheet metal. Anywhere I had good metal the Chassis Saver seems to have held up well. Seems pretty tough so that's what I plan to use on this project.

I've had disappointing results with POR15.

Our KK underbodies are painted, so there's no point in using ZRC?

How about a sturdy oil-based primer such as Rust-Oleum?

 

So the plan is to sand everything well and paint as much of the undercarriage as I can get to. This will be a several year process since I can never get at everything without removing a lot of parts. I'm disturbed by the huge heat shield that is above the transmission. I can't see how much salt got under it and what there is for rust/corrosion.

Painting should take care of the outer surfaces, but it's pointless to do it if the unpainted insides are not dealt with. I could really use some ideas on this part. How am I going to get the inside of everything coated and protected? All I can think to do is spray something like rust converter or oil in there and hope that it covers everything. The inside door panels can come off and I can paint the lower part where it always rusts at the bottom seam. The uni-frame rails, rockers and other body panels are another story. How am I going to deal with those areas? Rust from the inside is the biggest problem.

 

At this time, what you're seeing is just about surface rust.

If you want to get rid of rust? You need to either sandblast it, or if it's severe enough you gotta cut it off and weld in new steel. No paint or any magic stuff is gonna remove or stop rust. Only slows it down and lets it spread underneath.

 

POR 15 is awesome. Google it. Prep is important to get the full effect though. Always touching up little sections of my '00 with the starter kits. They do more then you think they would seeing how small the kit is. Another reason I use the starter kits is because people say POR 15 does not store well for longer periods. Also Fluid Film. That stuff is also awesome. Been using it the last two winters. Thing with Fluid Film is that it comes in spray cans but that can get a little pricey to do the whole underneath of a vehicle. Now if you have a decent compressor you buy the Fluid Flim Spray Gun Kit and buy gallon containers. One of the cool things is that both the spray cans and the gun kit come with these flexible wands. They spray out the end in a 360 degree pattern. Great for doing inside your uni-body. Fluid will wash off after some time. I spray it on good in Oct. Use a 1/2 gallon. To me this is not a less is more thing. It will not harm anything under there. It will burn off your exhaust for awhile though and you will notice a smell for about 1 week. Never wash wash the underneath of the Jeep all winter. Every little piece of crud will stick to it. I just run the Jeep through the $5 automatic car wash to do the body. Come Spring power wash it off. I would run it all year long but the Jeep is getting "refreshed" and with the Fluid Film underneath makes it messy when working on it.

 

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No stuff stops rust. Nothing. POR-15, Fluid film, or any other - they just slow it down and might mask the problem for a while, before it comes back even worse.
If you want to prevent rust, you gotta start preventing it the day you drive your vehicle off from the dealership parking lot when new. Once rust starts to form, it's a battle that never ends.

 

Oil stops rust. And phosphate kills rust, so does plain vinegar.

Have you ever tried rust reformer ? I've been using it on my Jeeps and it seems to work pretty well. I havent had the rust come back

 

My experience has been the same as you all mentioned. My XJ is real bad, because I couldn't keep up with it or didn't fix it properly. Someone undercoated it before I bought it which really made it rust out fast when the coating started cracking. Most of the rust probably came from the inside of the panels. Unfortunately it's the vehicle that I learned undercoating is not maintenance free. Hoping to have the KK last longer.

By the way can someone move this thread to the KK forum where it belongs?

 

Fluid Film. It works as advertised. Definitely not a gimmick. I have gone as far as to wire down a few test areas to bare metal and protected with nothing but Fluid Film, and it has stayed rust free for 2+ months. And by rust free, I mean entirely rust free, no tiny traces, no surface marks, no stain, nothing. I wipe with a rag, and it looks exactly like the day that I wire wheeled it to the metal. So I use it pretty generously, and continuously on my XJ. The winters up here basically salt/sand blast the Fluid Film off pretty quickly, so it's not a once or twice a year thing for me, I treat all year long, whenever I'm under the Jeep doing various jobs. If I tear something apart, I use it as an opportunity to treat any of the hard to get to areas I keep my rocker panels, bumper interiors, door inners, and most of the floor pan under the vehicle treated as often as possible. Its especially important to get it into any of the pinch seams on the vehicle, and it works itself in very well. I also added access holes to my rocker panels so that I can keep then perpetually treated. I also do the inside of the frame rails every few months. (I drench them!). It's also on the shelves at Lowe's now, which makes it easier to pick up when I need more (I used to have to order from amazon). Downsides? It makes working on the undercarriage more messy (it will not dry, but it doesn't attract dirt/dust like one would think), and its priced pretty high.

 

This. Ive started coating my vehicles with fluid film in the fall to help keep down rust. My 94 ZJ and my 04 kj wasnt caught early enough. The Zj's rust isnt bad, but the rockers under the plastic have holes all in them. I cleaned everything, coated the insides of the rockers and frame with eastwoods internal frame coating and everything else with their rust encapsulation paint. Then everything gets coated in fluid film. I bought their spray gun with the bottles that unscrew. Buy the gallons for $40 or so, Works great and it has a nice hose to reach everything.

The kj has a hole in a rocker also and I took VERY good care of that Jeep. Its a shame that jeep didnt coat the insides of the rockers better. You see a lot of WJ's with rusted rockers also. I literally sprayed that Jeep off everytime I drove it in salt and that still happened. I coat the inside of those rockers with fluid film also. Pretty easy to do when they have holes in them...

 

Why not buy a winter beater, you could save the Jeep for the rough weather conditions, and run the beater when they put the salt down after the storm?

Sent from my SM-T230NU using Tapatalk

 

I might do that this year. It's not good for the other car to sit so long between use as well. The challenge is that the weather changes quickly here and I commute 80 miles a day. So it's not always certain how things will go. But ultimately, I do want the jeep to last.

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I own two vehicles. Don't have funds for another which is why I need the KK to last as long as possible. My XJ is getting real bad. I can only use it to drive locally, no long trips. I can't trade up for anything new so I need to figure out the best way to make things last. I've had to learn to do all repairs myself for the last 20 years. It's been good, because I've learned a ton. All my vehicles run good before they end up as junk due to rusted out bodies. I could run them indefinitely if I could keep the sheet metal decent.

I was reading the internet about how you can get 360 degree spray nossles. This would be good on the end of a tube to coat the inside of things. Makes sense that you want it to soak in everywhere so it would have to be dripping out the seams and create a mess to get it done right. Might not be anyway around this. Will be using the hole drilling and rubber plug idea when I can't access an area.

 

If kept in a warm place and driven only in good weather, then you may be saved. If that was driven in wet/ winter/ road salt, all the rust would of course not come back immediately, but in over just one winter you'd be looking at small rust spots forming here and there.

I've had vehicles with way less rust damage, wire-wheeling everything seemingly clean, using rust-reformer and then a few coats of quality paint + lackuer, and even then the rust have come back.



Rust really is like cancer: unless you get even the smallest specks of rust off, it will come back. Wire-wheeling with an angle grinder won't usually remove all the rust, you need sandbalasting or replacing rust with clean steel.

 

I guess Ill find out in 3-6 months if it still looks like this or not. I wonder if i coat it with some oil and dirt back there too if itll help.. seems all my vehicles that are coated with oil and dirt are spotless when wiped away LOL. Problem with the wagoneer is the frame is fine otherwise still has factor paint and undercoat on but back here. And i didnt see this due to the spare tire hiding it all when i purchased it.. Then after i removed the tire i saw and i was like hmm.. well damn

I guess the good thing with these trucks is the frame can be swapped if it ever came to it


Ive also heard that coating the frame with a wax and lint seed oil or bar and chain oil for chainsaws keeps air/water and everything away.

 

There are at least 2 mechanisms for the rust to return.
The first is any rust left behind. Painting on top of rust with anything that doesn't chemically react with the rust just means you've just trapped the oxygen molecules at the surface...and it doesn't take a lot of oxygen molecules for the "rusting" oxidation to continue. I think we all know this.
The second is more interesting, at least to me. Paint likes to self level (most liquids do). On a smooth surface, this works great and leaves a uniform film thickness. When the surface is pockmarked from rust, however, lots of little sharp edges are formed. The paint thickness is very thin crossing over these (or is nonexistent) and is usually where the coating "fails" and the rust begins again.
The solution? Grind as smooth as you can, put down a base coat of a reactive paint, then multiple top coats of something thicker to build up over the high points. Brushed paints go on thicker than spray; consider something really thick like tar - just keep an eye on it over time so it doesn't dry out and crack, allowing moisture to get back down to the metal.

 

One of the main problems with a lot of paints is moisture/oxygen getting through the paint and causing the metal to rust. Obviously paints have gotten much better over the years. Products like POR15 and Chassis Saver are supposed to keep this from happening. Like you say the main problems would be poor adhesion where the paint gets compromised in some way. High spots and corners where the paint is thin. Unpainted surfaces like the inside of panels are a problem. Things rust from the inside out no matter how good your coat of paint is on the outside.

 

This thread still needs to get moved to the KK forum. I guess it's realavent for XJ's also, but that's a different major project that I'll take on at a later date. I need to get a welder and replace a lot of metal on the XJ.

 

Removed plastic rocker covers and found plenty of salt and dirt under them even though I wash thoroughly. Are they trying to fix the rusting out rockers by having a plastic cover? I think the problem is made worse since you can't actually see and clean the metal rockers under them. I would love to leave off the plastic rockers and do something different with the fender flares, but there are big voids where these parts are installed. They are not just protective covers, but actual parts of the body that need to be there. Pretty lame.:thumbdown: I guess I'll be breaking more plastic mounting clips every time I have to remove the rocker covers to clean. Broke 5 of them. There's no way to pull out the plastic clips without breaking them, because of their design. No way to get a pliers inside the rocker panel and squeeze the clip. Will see if I can get a different style clip. After owning an XJ I find the KK quite annoying the more I learn about it.

 

For starters I'm repainting from the stamped frame rails out to the rockers panels on both sides. Next will probably be everything I can get at by removing the the fender flares and plastic wheel wells. After that front and rear end. Lastly the middle of the Jeep where everything is in they way. Motor, transmission, fuel tank, etc. Not sure when or how I will get to all those areas or if I will. Also have to pull the door panels and do the inside bottom. Oh, and all the suspension. This will never end.lol. I should just buy a Wrangler kit and paint it right before assembly.lol Here's a photo from before any prep was done.

 

Photo after sanding with 180 grit. Felt wrong to sand perfectly good paint on a low mileage vehicle. I know what will happen if don't take care of the inadequate paint job though.

Started out using an orbital sander, but that just blew through the paint as soon as I touched it. Ended up sanding it all by hand so get in all the crevasses. Even then I had to be careful not to sand through the paint. The undercarriage paint is thin, another bad idea. Also removed a bead of expanding foam on the back of the rocker. Apparently it's supposed to keep crud out of the seam. I found that it trapped moisture and the seam was starting to rust under the foam. It will get a nice coat of protective paint now and seal the seam properly.

 

So I was going to put on a few coats of silver Chassis Saver today, but I chickened out based on what I just read on the internet(love it hate it).

Paints like POR15 and Chassis Saver do not bond well to smooth surfaces. Chassis Saver instructions say it's best to sand blast or go over tight rust for best adhesion. A secondary option is to sand bare metal with 60-80 grit. To apply over old paint they say to sand away all traces of gloss with 120-180 grit. This is what I did, but sanded through in some spots and couldn't get the gloss off in all the crevasses. Not sure that I'm going to get good enough adhesion. I need to be able to pressure wash the road salt off pretty regularly.

I sent Magnet Paints and email to see if I would be better off applying a rough coat of primer first. I want to make sure I get it right the first time. I don't want to sand until my fingers bleed again.lol They also say a wire wheel is a bad idea since it leaves the metal too smooth for proper adhesion.

I need to get this painted by the weekend so hopefully I hear back soon and can get primer locally if I need to go that route. Hopefully primers come in different textures.

 

I would clean the salt and other grime off, then drench the entire thing in Fluid Film, I would also make sure to get -inside- the rocker panels (even adding a few holes if necessary) and then put the plastic covers back on.

Then repeat every year or so. Although because that area is so protected from direct contact with road particles, the fluid film will stay in place for a very long time.

If it is covered with Fluid Film, it is not going to rust easily at all, -and- if it should start to rust anywhere you will -see- it right away. That is the problem with paints and undercoatings - is that when rust happens under them (and it will) you won't know about it until it is truly awful and coming up through the paint or undercoating).

Por15, Chassis Saver, and Fluid Film all work on the same concept. Keep moisture and oxygen away from the metal. And they can all be successful if the application is correct.

But paints and undercoatings can't creep deep into pinch seams, around corners, and heal themselves in places where they were scratched or rubbed (or missed entirely). They also make the metal invisible to inspection. So especially on anything "internal" or hidden by an external plastic panel, my preference would be Fluid Film.

I'm not saying its magic (though I have been using it in high-salt high-moisture environment on my XJ and it has been as effective as the manufacturer claims). I'm just saying that it matches your application well, is reasonable in terms of cost, and will give you the most amount of flexibility and ability to inspect over time.

 

That's likely what I will do. Paint everything I can get to and use Fluid Film or some type of oil that will wick into the seams. Sounds like a solid plan.

 

Yeas adding more holes helps alot for ventilation and drainage.. I did the same to my 5.9 and 4.0 rockers. The 4.0 sadly has rocker rust on the passenger side but the drivers is ok, and my 5.9 has a tiny bit of rust but not enough to really worry me atm.. So i drilled a bunch more holes.

I gatta tell you the rockers on your Jeep are very small lol.. With the plastic removed and pics of the underside these Jeeps dont even have real solid frames anymore i guess. They are like sections of plates and stuff.. I wonder if thats for like "crush" zones

 

Never got a response from Magnet Paints. I followed their instructions exactly for going over existing paint. Hopefully it holds up. Will be a horrible experience if it doesn't. Can't tell you how many hours I spent on the little bit that I did. Quite a few. It was a pretty messy job painting upside down. Figured out the best way to do it is to roll on the paint and then brush it. I thinned it out pretty good, but it still left brush stokes since it was starting to set up almost instantly as I applied it. Which means there's not a uniform coating thickness. Painted everything twice and the welds/seams/corners got three coats. Used probably 2/3rds to 3/4ths of a quart. Need to get a couple more cans before I can continue. Would be nice if I could find it local.

 

Here's how I took care of the broken clips for the rocker covers.

 

Painted the spare tire and carrier. The carrier won't last the life of the vehicle if you drive in road salt. It is thin stamped metal that is riveted together. The cable appears to be stainless steel so I'm thinking it will outlast the housing.