What can I do for rusty fenders?

I am considering the purchase of a 1988 4Runner. One of the few serious flaws on it is what appears to be deep-seated rust along both rear fenders. There are no holes or anything but it is bubbled up under the paint. Do I have any recourse to fix/halt the rust progression besides replacing the fenders? And of course, if so, what? Thanks.

Unfortunately, where there’s a little surface rust, there’s usually a lot of rust you can’t see. The bubbling paint type is actually some of the worst, because it means it’s rusting from the inside out. It is highly unlikely that the rust is only contained in the fenders, too, so replacing them would probably only be a cosmetic repair.

That said, this is a truck with a solid frame, and if it is actually only rusting superficialy on the body panels, there’s no reason you can’t drive it around as is. I’d definitely take it to a mechanic before you buy it to determine the extent of the rusting and confirm that it’s safe to drive. Also, as the rust is eventually going to become terminal, I probably wouldn’t pay more than about a thousand for the thing and expect to get no more than a few years’ use out of it.

What are the other serious flaws? You said it has a few?

If you live in the rust belt, you should know that rust never sleeps.

The bubbling paint that you see is only about 30% of the amount of rust that’s really there. So if you were to try to remove this rust, you’ll probably have to clean an area three time larger than what’s seen.

If the rust is only surface rust, then the area would have to ground down to bare metal. Then a metal prep for rust, such as EXTEND, would have to be applied to the rusty surfaces. Then you would have to prep and paint the area.

If the rust is totally through the metal, then the only fix for this is to cut out the rusted section, and weld in patch panels.

In either case, it wouldn’t be worth the trouble or expense to try to fix the rust on a vehicle this old. Because once you fix one rusted area, a new rusty area shows up a short while later.


Get some serious estimates on rust/body repairs. An 88 4runner if in a salty area is likely junk now. Toyota trucks up till somewhere in the mid 90’s are abysmal with rust. My family has three and two of three demised of rust not mechanical repairs at an early 10 years old.

“Replacing” the rear fenders on a car is not a nifty little procedure like it is on the front. You have to cut out the rot, weld in a patch, mud, primer, prep, paint… it’s a weeee bit of a pain. On an '88 4Runner it’s probably a weeeee bit more than twice the worth of the rig. The other posters are right on the money when they say that visible rust is probably just the tip of the iceberg. Be wary.

I don’t recommend a 1988 4-Runner. The problems have only just begun.

Aw, man! You guys are crushing my groove. In response to all of your comments, there really are no other serious flaws that I can find. Granted, I don’t know what the engine has been through, but I have confidence in even a somewhat mistreated 22-RE. I do not live in the rust belt, but with our saline atmosphere in coastal Virginia, it’s the next best thing. You’re all right in that the rust is likely to continue from here. The truck has been painted at least once, somewhat recently it appears, but the rust is showing through already. Basically, I’ve always wanted a first generation 4Runner, especially since burying my 92 after a long, full life, so I got excited about this one. The rust was just enough of a red flag to compel me to come here before deciding anything for sure. Thanks for helping me quell my excitement long enough to make a more logic-based decision. I may still buy it, but I will be offering much less than the asking price, with no expectation of a miracle.

Good plan. If you get it cheap enough, then sand down the rust areas, both sides of the metal. Remove as much rust as possible. Treat the exposed metal with Naval Jelly or any other Phosphoric acid conversion treatment, them prime with Zinc Chromate (NAPA). After that, fill any holes or deep pits with Bondo, reprime with your choice of primer and paint. After that, do at least a once a year rust inspection and treat any new rust spots the same way.