By far, the most common rust problem is on 1979-1988 trucks on the seams between the upper sides and lower quarter panels and the spot welds above the wheel wells. The box floor also rusts out to the point of being unsafe to walk on. As you can see in the above picture, this box floor looks like swiss cheese. The only thing holding the box sides on were the bolts at the front joining the sides to the front wall, the bolts to the topper, and the tailgate holding the topper up. We originally planned to use a sledgehammer to take the sides off, but they pretty much fell off when the topper was removed. The sad truth is that this is pretty typical for early Toyota trucks. Check out my fiberglass bed section for a permenant fix!
There are plenty of other rust zones too. The bottoms of the doors on 1979-1995 Toyota trucks and 4Runners rust out to the point of seperation of the inner and outer shells. 1984-1989 4Runners rust out around the rear wheel wells and tailgate to the point of massive amounts of missing metal. Even 1990-1995 4Runners have a serious rust problem--the rear wheel wells, door bottoms, and tailgate rust out pretty bad. I saw a 1990 4Runner that had a good two inches of metal gone all the way around the rear wheel wells with an additional two to three of rusty metal around the perimeter. The bottoms of two doors were separated, and the tailgate had numerous holes. Though this is a little worse than average, it's a sign of things to come. The severity of the rust problem on 4Runners is made worse by the fact that patch panels are not available for the rear wheel wells. An entire new side must be purchased directly from Toyota. 1995 Toyota 4Runners are still pretty new to be rusting severely, but I have seen them with popped door seams and quarter-sized bubbling on the rear wheel wells.
Another rust spot is the frame itself. Most 1979-1983 Toyota trucks here in my town have a cracked frame. It is what puts most of them in the salvage yard. A patch job can be made to the frame, but most often it is only temporary becuase there is rarely any good frame metal left to weld on new patch metal. The most common spots to find rust holes or cracks are from the back of the cab all the way to the end of the frame, especially in the diagonal section where the front mount for the rear springs is located. Any time I purchase Toyota, I always reach in between the gas tank and frame and feel for a hole. It is pretty common for there to be holes and cracks next to the gas tank. My article on rusty rear brake lines goes into more detail about this. It is not uncommon to find a two-foot hole on the inner side of the frame rail here. I have found rust holes and cracks just about anywhere on the frame. I have even owned vehicles newer than 1983 that had poor frames.
The solution for rust prevention really depends on how bad the problem is where you live. Minnesota is probably near the top of the list for having the most severely rusted vehicles. I have spoken with many people from the South via E-mail and many of them had no idea vehicles rusted this badly. Short of replacing the bed, rust prevention ranges from regular washes/waxes to cutting out rust and welding in patch panels. Most all of the usual techniques for rust prevention do not help much, if at all, here. These include weekly washing/waxing, routine rock chip/scratch touch-ups, and patch panel repair.
I have performed virtually every kind of rust prevention technique possible, and nothing worked except for the technique of applying gear oil (or another thick viscosity oil) over the rubberized undercoating. bought my 1985 pickup in 1991, it came 100% rust-free from California. I did weekly washes in the winter time, I routinely touched up rock chips and scratches, and I waxed it about once a month. Incidently, removing the mud flaps is not a good option if you live in the Rust Belt. Yes they may look ugly, but so do large rust holes. I also had the truck professionally undercoated including the body panels. Within 3 months of purchasing the truck, I got into an accident and had the complete passenger box side replaced with new metal and undercoated again. After just one winter the box seams were bubbling pretty good. After a few winters and a lot of prevention work, I found holes in the spot welds above the wheel wells. I sold the box shortly after that. I had many, many hours into rust prevention, and the box was still falling apart. And much to my surprise, the new box side was rusting much faster than the original side (11 years old at this point).
My father's 1986 Toyota 4x4 had even more work done to it, and it faired much worse than my truck. He purchased his truck in 1990. It did not have any rust on the box, but it looked like it had been repainted. Within 5 years of ownership, he had the box repainted 3 times. The first repaint included standard sandblasting and replacement of the seam sealer. The second repaint was more sandblasting, replacement of the seam sealer, and then bondoing over the seams. The third repaint consisted of sandblasting and welding the seams shut from the outside. By 1997, the box looked pretty bad. It's the white one pictured below, and these pictures were taken in 1997.
Rust free used parts are at best rare and typically non-esistent. We have businesses in my town that specialize in hauling up used automobile body parts from the South and reselling them here. They never have any Toyota parts, and they have a waiting list. I put my name on the list a few years ago for a replacement box. It took about 2 years before I got a call back, but I already purchased a fiberglass bed. The shop said they are lucky to get one or two Toyota boxes a year. They typically ask a minimum of $600 for a box without a tailgate or tailights and up to $1100. These prices also apply to the older 1979-1983 Toyotas because it is impossible to find a used box, and a new one from Toyota costs around $1600. I have looked at a few boxes before in the $600 price range, and each one of them had rust bubbles on the seams, dents and dings, and beat-up box floors. The problem with spending $1600 on a new box from Toyota is that the same rust will happen, and even faster. Why faster? Well, no paint job seems to last as long as the original baked-on finish from the factory. A new box from Toyota has to be seam-sealed and painted by a body shop, and though the quality of paint work in the autobody field is improving every year, it is not anywhere near as good as the factory paint job (and as we all know the box was designed poorly to begin with).
We see worse than average conditions here, but it is a sign of things to come for the rest of the country. Hopefully my article will help you out and even help you avoid false hopes, wasted money, and wasted time/effort. I hate to paint a grim picture for you, but it may help you make some important decisions. This rust problem is why used Toyota body parts are in such high demand and is also why these used parts cost so much (at least around here). I part out a few vehicles every now and then. Rarely do I come across good body parts. I have a few now, and you can find what I have by going to my For Sale page and looking at my parts lists. If you are not from around this part of the country and find that our parts pricing is much different than in your region, this article should help explain why. Except for this rust problem, Toyota makes a wonderful vehicle.
Door Seams
Box and tailgate
Front Fenders
Cab Rocker Panels
1989-1995 Pickups:
Door Seams
1984-1989 4Runners:
Door Seams
Rear Gate
Front Fenders
1990-1995 4Runners:
Door Seams
Rear Gate
Rear Wheel Well
