Undercarriage rust

Depends where on the undercarriage it is, and how much you want to spend on the car. If you want the cheap way, just to keep it nice a couple of more years, then you can do it yourself. I suspect your talking about the floorboards. That sheet metal is pretty thin.
But what I would do is sand it down good and apply some "rust converter" found at any autoparts store . Turns the surface rust that remains a black color, sealing the metal and or a convertion of the rust back to metal. Spray it up with some paint, color of your choice, and drive it.
Start saving for a resto job for the future.

If its just surface rust, it'll be easy. Sand it down, paint it, and get the undercarriage oiled regularly. Your undercarriage doesnt sound too bad for a Canadian car..

Take a screw driver and stab around at the floor.. if it goes through anywhere, then you have a problem!

How hard is it to repare rusted floorboards?

I am in the process of that now I removed seats console kick panels and doorwell trim seat belts that need to be. Then ripped (carefully) the carpet it is tricky by the e brake lever.What I found was not too pretty. I then checked brakelines under the area and undid the bolts holding it to the floorpan. Then with my grinder and cutting disc and glasses cut out any ^&^% areas. There were a few. One big one from behind the front two bolts on the pass side to the back. I scrounged some small angle type steel I am going to use as a seat for the new plate then bend it the way it looks best then weld it up. After that I plan on some type of steel bondo underneath then cover it up with some type of under carriage paint and be done. If the floors have rust there are likely more. I removed the plastic inner fenders of mine and was not too happy about that either. More work is all. I plan on spraying all the unexposed steel in my car I casn not see the harm it should only prevent rust. Only 3.00 Can a can for cheap stuff. Good enough for some areas of the car. So I think it is not too hard of a job I am not near done yet though but I cannot see paying others to do this type of work. And if there is no way to weld you can rivet instead.
Good luck.

If your floors have rotted through, meaning you can poke a screw driver threw them, the CORRECT way to fix the problem is to replace the whole floor pan. Im doing that now, and its an ugly job. You have to drill out all the welds all along the pan, as well as the seat bracing etc. - after thats all done, you trace your new piece onto the old floor, cut it out and weld the new one in.

Or you can just buy complete, perfect-fit replacements: Fox floor pan

God I love cars that they make so many aftermarket/replacement things for....

There are more ways than one to skin a cat you know. So as for CORRECT that would be your version of correct but I cannot see paying 170 for the whole thing when I only need a part and my car is not a show car. As long as I know it is solid and it looks good to me I would prefer to save my money and my time to pursue otheraspect of my car. For my situation that works just as good for me and just because it does not look exactly as the other side it will be just as strong if no stronger last just as long if not longer and no one else will know the difference. It, I think depends on the situation. Not what is or is not correct. CORRECT me If I am wrong... or Incorrect.




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if its only surface rust then what you can do is just get the car up off the ground nice and high. remove anything you can to give you good access to the entire floor. clean it and scuff it up with some 400 to get the surface rust coming off. once its nice and clean and the rust is pretty much gone paint it with por-15 or any other rust inhibitor of good quality. i prefer por-15 or a products from eastwood. once its all nice and dry put it back together and dont ever worry about it again. por-15 will stop rust in tracks as long as it hasnt eaten through completely.