Like the title says, I have underbody rust. Curently I've only found cancer on the drivers floor pan, and a bit on the steel beams under the car. I plan on cutting the badly rusted parts and riveting a peice of sheet metal to patch it up, as for noncancer rust, I figured a good sanding and painting (mabey a bit of bondo) would do. The body panels have a very tiny bit of bubling paint, but thats also getting sanded and primed (paint job comming in the fall) and there is a little door sill rust too which I could easily sand off. Any body have any advice or input?

 

Make sure to check the wheel wells where the lower trailing arm bolts to the chassis. That area is notorious for rust on these cars and can be very dangerous if the link rusts out.

 

The Front Frame rails behind where the Idler arm and steering box mount also tend to rust out. Acutally a while back there was a post about where the 1st gens are known to rust out...Do a search for it under my name. As far as advice, Make sure to clean the surface as best as possible because the rust will spread to the new metal if you dont

 

this is what i'm working on... Hopefully your car wan't as bas as mine!!

 

If you plan to put a lot of money in the car I would suggest a clean shell first.

 

I gutted the car's interior and put it on jack stands and it turns out the worst rusting on the car was just the drivers side floorpan and I also caught some wheel well rust (not to bad) which mysteriously seemed to start on the inside of the car.

 

I would not know much about underbody rust. My 83 has an engine oil leak that eventally completely covered the entire underbody with fresh clean oil.

 

If you have a sunroof, clean out the 4 drain tubes. Also check the the door gap at the top of the door for a tight seal.

 

The weather stripping was really trashed when I got the car, it was basicly rotted off I replaced it since. I just found that the cancer on the frame rail has spread to the adjacent lines running under the car so it looks like new brake and mabey fuel lines are comming.

 

yeah check the sunroof iv got rustnear the front corners
i thought i was rust free till i stripped the interior im hoping its not through the roof ahhhh