I did the rocker panels on mine 3 years ago. My van never had alot of rust. When I bought it in August of 2001, it did have bulging between the plies and very minor rust through on the sill of the passenger front door. It never got much worse, though. When I fixed it in 2007, it only had pinholes in the one under the driver door and a hand sized hole in the big one on the driver side. It had a silver dollar sized hole in the dogleg and some moderate sized holes under the sliding door. I bought aftermarket rockers.
Even though mine never had much rust, I still had to do some serious patching of the inner structure. Most of the bottom of the inner rocker was very thin or gone. The bracing inside the front rockers was also bad and I just cut it out as it is near impossible to patch it and re-weld it blind. My new rockers were alot heavier guage than the originals and would more than make up for the weakening of losing the inner bracing. It is also less likely to rust as it is now all single ply in the sills.
The one under the driver door was a piece of cake. I just used the part you can see from outside and spot welded it just inside the door jamb. I calked it smooth and it is nearly invisible. Still looks good after 3 1/2 years. I could have done it perfect with Fusor and Bondo on the seam where it steps up to the sill inside the jamb. .
The big one behind the driver door was a nightmare. I made the mistake of trying to use the whole panel because I always try to weld between two bodylines if they are close together to cut down on warping. Well, the top bodyline on the POS aftermarket panel is not formed right for this and was not bent anywhere near the right angle. I had to rebend it on the brake and the bodyline doesn't match exactly with the door. It also needed some massaging near the wheelwell as it is doesn't have the complex curve to match the slight flaring of the wheelwell. If i did it again, I would use the least amount necessary of the new panel and Fusor it on to eliminate warping. If it would have had the flange for the seam as the OEM panel does, I would use it all and Fusor it on just below the seam after spreading existing the seam and forcing a small amount of the flange into the seam.
The passenger side one was the worst. Again, I tried to use all of the panel because it was actually alot less welding. The rocker I got was not anywhere near the right contour. I used the whole damn thing and almost all of what I welded it to was the factory structure. I also made the mistake of doing it with the doors off. Well when I went to bolt the doors back on, the edge that runs along the door openings was 1/2" too high and 1/4" too far back. I ended up having to mount the doors so they slightly overlap the rocker. When you buy this Chinese crap, you never assume it is formed anywhere near correct, even though it is just as easy to do so and looks real pretty. This is on a vehicle that has new paint from the windows down and will look like it rolled off the showroom floor after a little polishing.
I also didn't weld them along the pinch weld on the bottom. I bought a box of 1/4"X3/4" pan head bolts and nuts to attach them there. That way the undercoating on both the inside structrure and the rockerpanels wouldn't be distrubed to cut down on rust.
I really don't recommend doing what I did if you are restoring the van to the level I have. Most Aerostars in my area have coilstock pop-riveted to the big rocker and more coilstock or duct tape on the smaller ones. The aftermaket panels are a good alternative to this for a rough-n-ready job, probably pop-riveted on over the old ones and spray bombed at most. They would also be good if you are using just small bits of them like I should have done. When you go to the trouble I did, I would use OEM panels if you can get them.
When you get down to it, these vans aren't really worth the money it takes to fix them right, which is a shame because I prefer it to the 98 Explorer I had. Probably the best way to get a really nice AWD unit is to find a southern or western 2wd van with no rust and transfer the trans, transfer and front end to it. It would probably have been less work that what I have in mine. Especially if you can find one with nice paint. I probably have 50-60 hours it including the Bondo, glazing and paint. I'm never going to get that back when I sell it. Having to deal with rust down the road is the main reason I don't plan on keeping it for a long time.
