rust!

[oldsub86]

Yeah, I know these cars are getting old and rust is always an issue. We had quite a bit of rust repair work done on the back part of the car last spring - the typical rust on these - rear wheel arches ahead of the wheel by the back doors on both sides plus some work under the back bumper to close holes into the trunk.
The current problem is rust near the radio antenna on the left front portion of the roof. It appears this has been repaired before with bondo and the water is getting in. A piece of the bondo has cracked and it is letting water in when it rains. The result is that we are getting a drip from the top edge of the windshield inside.
It is also a bit of a structural issue as the windshield has cracked in this spot as well. Going to have to grind it out and have a look. (ie - I would like to do it myself it time permits) Messy as it will require removing the windshield and the headliner in due course to repair properly.
Anyone else have this problem and make the proper repair?

[danronian]

I have basically the same rust spots as you. But my rust hasn't yet cracked the windshield and hasnt been repaired yet. I fixed rust just like this on my chevelle though. Like you said the first thing you should do is take off the antenna plastic, antenna, windshield, any interior tirm directly behind the repair, and trim around the windshield. Then use a cutting wheel to cut out the rusted portion, but make sure you know what the contour of the piece should be for the new metal (I always make a cardboard template before cutting the rust). Then you want to also get the paint off the surrounding area. Then you simply buy some good galvanized sheet metal and rivet (or weld) it into place. If you use rivets, first make the area lower then it should be (hammer), then grind off the heads of the rivets, before riveting the metal be sure you paint the metal and the surface which the metal will cover and also use silicone or body cement under the metal to stick it to the surface. Then I also paint the part which is going to be fiberglassed before doing the bodywork. Then if the divit is deep enough use some "tiger hair" fiberglass filler, but it it is not just use finishing platics or bondo filler. Do many thin coats of bondo and use a block to sand it down. Initially use grits like 120, then 220, 320, 400. I generally go to 400 and then use a spot filling primer to fill bondo air pockets with, that or use spot filling puddy. Then sand the primer with 400, primer again, sand, wipe, then topcoat.

[Dibbs]

Couldn't have said it better bro!

[danronian]

Thats from doing an entire summer's worth of bodywork on the Malibu. I probably used an entire 3g's hood worth of sheet metal on that rust bucket. But no bubbles yet, year and a half and counting....

[MrBen]

Block sanding the many thin layers of bondo on my trunklid worked great. I probably put about 15 layers of bondo on there. It paid off though, because it is smooth as the rest of the body and you cannot tell that bondo was used to repair the dent.

[danronian]

Do you have a pic of the final repair? I really wanted to see how it worked for you.

[iamvandemon]

bondo... fiberglass.. sheet metal... whatever you decide to use make sure you start out with "por 15" it is the only thing that will stop rust permanently. (if you follow the directions that is) if you don’t "por 15" it the rust will come back again just like it has from the previous "repair".

[MrBen]

I don't, and I wont be able to for a while until I get to my friend's house who has a digi cam. I have pics from before, I dunno where the hell they are but I'll find them.

In the meantime, it looks great, and I hope that the bondo doesn't crack etc any time soon.