I (as you can read) have a 92 ssei I just picked up this weekend.
There is a bit of rust on the trunk below the lights ..just a bit.
It has a bit of rust of the body....mainly in the wheel wells(sp?)and there is a bit of flaking, and above the right rear wheel there is a little bit of bubbling on the exterior paint surface. The underbody appears to be somewhat of a rusty colour.
How do I grade the stage that the rust is at? And what can I do before it gets too bad?

Do you have a digi cam ?? Take some pics of it.. most rust has to be taken out before it cancers out and eats right through the metal.. in which case you'll have no choice, but to replace it or bondo ( fibreglass )the crap out of it. Unfortunetly.. there'* not much you can do without costing money ( panel replacement ) or have blotches of paint all over the car.. even though its suppose to be the same black color. Take a pic and I"m sure we can go from there..

I used to own a 70 Dodge Coronet, so I have terrible experience with the rust thing.
:(
Best thing to do is cut it out, replace with sheet metal, and construct fiberglass around it to give it a strong mold. If it gets to bad though your gonna have to get whole new panels, and that ain't no fun.

Ya I do, I'll take some pics of the rust and post asa I can....

Thanks!

I've used a Permatex rust stopper successfully in the past. It worked for a few years on my 77 Camaro. But being a Chevy that grew up in the Great Salt Lake area, the rust finally won.