What to do about random rust on body?

I have a '99 XJ that is in overall great shape. Very little rust, great paint still, etc. It is developing random rust spots and I want to do something about it but don't know what. From the pics below, youcan see just two of the places that it's beginning to show through the paint.

The places that have me the most concerned are beneath the windows on the rear side cargo windows. It seems to be developing under the rubber window sealer and can't really get to it.

What can I do? Is my Jeep already doomed to rust away to nothing, or can I do something now so that it doesn't get worse and possibly prevent it from spreading? Any input would be greatly appreciated.

Remove the rust, treat the bare metal with acid, prime with rust resistant paint, apply body filler as needed, and top coat to match your original paint. A wire wheel works for rust removal, sand blasting works best.

The side rear windows are simple to remove or install, if you are careful. Flex the rubber seal/gasket and pry it out. Use some 3/8" cotton rope in the gasket to reinstall the glass or have a shop do it.


Google for paint and bodywork info, glass info, or buy a book on the subject.

X2. I'd bet on that rust near the glass starting during a bungled rear window replacement that chipped the paint on the pinch seam under the trim.

The fender one isn't that bad, at least. Looks like it's coming through from the backside though or perhaps from the holes for the two self tapping screws holding the bumper endcap onto the fender edge. My 96 has a similar issue where the headlight surround is screwed into the leading edge of the fender.

Thanks for the good info. I washed the XJ yesterday to celebrate Memorial Day and discovered that this past winter was not kind to my XJ. I discovered rust on other pretty random places, but mostly starting to form on the underside of some of the doors. Now that it has started, will I basically be doomed to patch up rust here and there for the rest of the time that I own the XJ?

I have access to doors of the same year and color that have no rust. Would it be easier just to swap on the doors to mine and call it good, or does that just seem silly?

jeeperguy21 said:

I have a '99 XJ that is in overall great shape. Very little rust, great paint still, etc. It is developing random rust spots and I want to do something about it but don't know what. From the pics below, youcan see just two of the places that it's beginning to show through the paint.

The places that have me the most concerned are beneath the windows on the rear side cargo windows. It seems to be developing under the rubber window sealer and can't really get to it.

What can I do? Is my Jeep already doomed to rust away to nothing, or can I do something now so that it doesn't get worse and possibly prevent it from spreading? Any input would be greatly appreciated.

Click to expand...

First: If you're one of those guys who subscribe to the belief that "if it ain't muddy, it ain't a Jeep" or some similar crap, then deal with it & quit whining ( ).

However, if you have common sense (and I think you do), continue reading. You can fix what's already begun & work hard to prevent more. Wire wheel/sand/scrape etc. existing surface rust like explained above.

Prevention is easier than curing. If you have snowy winters, pressure wash your undercarriage during the winter time as often as is practical. Wash it after muddy wheeling (even tho you're in Utah the Jeep God's heaven). I've been known to blow $30 at the carwash following a wheeling trip before washing the body. A clean XJ is a longer lasting XJ. Paint is your friend. You might look prissy to your friends, but you'll have the last laugh.

Oh, one more thing: don't be afraid to peel back the carpet one of these days - to make sure you don't have any nasty surprises festering under there. Ask me how I know ... :banghead:

Yeah... Check under that carpet. I was in denial for 2 years and all it got me was a week worth of work instead of a few days. Not looking is kinda like not getting xrays and just hoping for the best :dunce: anctually exactly like it.

The doors rust that way because water and junk from inside collects in the pinch weld where the door skin is welded on, not much can be done about it after the fact since by the time you see bubbling there's already a ton of rust in there. I would buy the doors you have access to, then stick em in storage till you feel it's time to swap them.

UPDATE: I went to a car paint shop last week and got some materials to fix the rust. I sanded the rust and paint down to the bare metal with 150 grit sandpaper until all the rust was gone. I then applied two forms of primer on the metal: a prep primer, and a filler primer. After letting them dry overnight, I sanded them down so they were even with the body. I then painted them with an enamel spray made from the color coding of my Jeep. The result was wonderful.

I have included some "after" shots of the two places I took pictures of in the first post.



The repairs aren't perfect because this was my first time, but I couldn't be happier with the results. The rust by the front fender has me concerned though because I think that it may be rusting from the inside and showing on the outside. This may only be a temporary fix for that area. I can't access that area on the rear of the panel either because there's too many things in the way. I'm hoping that I'm wrong, but only time will tell... probably a couple more winters will reveal the truth.

While I was at it, I kind of went nuts with repairing the rust. I searched the body high and low and fixed it wherever I could find it. There were small bits of rust under almost all of the doors. They all look brand new now. Some of the hinges on the rear doors were really rusty, but look great now. I didn't have any "before" shots of those, so I didn't bother taking any "after" photos of those areas.

After a wash and wax after repairing the rust, my Jeep now looks years younger. I was surprised at how easy it turned out to be. It is just time consuming because it takes time to sand the rust away down to the bare metal in awkward areas, like the door hinges. You also have to tape off each area you are working on so you don't paint things you don't want to, and you have to wait for the primer and paint to dry.

looks great! Did you pull the window out when doing that fix or not? If you didn't, I hate to rain on your parade but there's a good chance it'll come back sooner rather than later, water will continue going under the window gasket and the rust will creep back out from under it.

The front fender I would not worry about too much. That is a bolt-on piece of sheetmetal, at the very worst, all you have to do is pull the fender, buy a new one for under a hundred bucks (or less if you find a good one at the junkyard - especially if it's from your year and paint code!) and slap it on.

I didn't have to remove the window. There was an obvious chip in the paint, probably from a botched install, that was very easy to get to and repair without having to remove the window. I was able to eliminate all the rust that was there and give it a proper repair. There was no other damage that I could see, but it would have been a helluva lot easier to fix without the window in the way.

This is where I put glass coverage on the jeep, wait a month, and then resurface the window with a 3 pound hand sledge :eyes:

Great :thumbup: I hate rust.

It was a great feeling to be able to stop the rust instead of letting it eat my XJ alive. I have let rust win the battle in previous cars I have owned, but I am going to do whatever I can to with this battle. I wish I had a beater 4x4 that I could drive in the Utah winters, but this is my primary vehicle, so I'll just stay on top of the it when it crops up again in other places, which is sure to happen here.

looks awesome! im going to do the same thing on my XJ this spring. i have the exact amount of rust in the same spot under the rear window. i must ask though. how did you blend the new base/clear coat to the existing 10 yr old paint thats on it....it looks like a perfect blend.

were you stuck having to buy a full pint of automotive paint from your local store? or did you use something more along the lines of a touch up pen?

i know just a pint of matching paint can run like $50+

Sand the paint down to pure metal and eliminate all rust.
Treat rust if necessary with rust neutralizer.
I then used two types of primer: a base primer, and a builder that you can sand down to make it even and pretty before the coat of paint.
I bought a matched rattle can of paint for about $15 from a local auto paint store. After I had painted everything all up and nice, I buffed it up nice for the final blend that you see above. It still looks nice after a rough and salty winter. Let me know if you have any more questions.

cool! yea i cant wait to try it, prolly this spring wen the salt and snow is off the roads....

how far around the rust spot did u sand down? did u tape it at the body line or blend it?

no clear coat? just the rattle can?

I taped around the area I was working when it came time to paint. I sanded it until all the rust was gone. No sense in overdoing it. The paint I used didn't require a clear coat, but do whatever you think will turn out the best.

ok thanks! every thing helps when doing a first time attempt like this. ill let u know if i have any more questions