Auto body repair & detailing: 1997 Land Rover Discovery, harbor freight tools, land rover discovery

Question
I own a 1997 Land Rover discovery that has developed some rust in the area where the rear door closes by the "wheel well".  Considering I use the truck for 4X4ing and am not terribly concerned about esthetics.  Can us advise me how to remove the rust and rplace/repair the area that has been rusted out.  It is a circular rust spot about two inches in diameter.  

Answer
Rust is one of those problems that once started is nearly impossible to stop. If the rust started from a scratch on the outside of the panel you're going to be in much better shape than if the corrosion is on the inside rusting out. The best way to deal with the problem at this stage is to cut the rusted section out and replace it with a new piece of steel. Planning ahead to ensure that you don't leave the inside of the new panel bare will be key in prohibiting rust from developing in the future. First you'll need to find a piece of steel that can be used to replace the section that you're cutting out. using a screwdriver or something similar break out as much of the rusted area as possible. Now feel or look inside if possible and see how far the rust extends to the sides of the hole. Hopefully this will be minimal. If the rust does not extend beyond the hole or at least not very far beyond the hole you're in good shape. Trim the new piece of metal so that it is 3/4 of an inch or so larger than the entire section discovered to be bad (including the extension of rust on the inside of the panel). Now lay the new piece over the hole and trace it with a fine tip felt pen or sharpie marker. You don't want to use a thick headed sharpie as you're going to need this do be as accurate as possible. Now you're going to need to cut this section out of the panel. A die grinder with a cut off wheel is ideal but you may be able to get away with a sawzall or a hack saw blade depending on the location of the rust. Die grinders are very inexpensive at places like Harbor Freight tools. They have locations nationwide or you can go to their website and order a die grinder and a cut off wheel adaptor. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93389
Once you've got the old rusted piece out test fit the new patch and trim as needed in order to get a tight fit. You should do whatever you can at this point to prevent the rust from coming back. A trip to your local auto body supply store will be worth the time and money. Get a bottle of Osfo rust inhibitor and a spray can of weld through primer. This should cost less than $20. Treat the inside of the quarter panel and the back side of the patch panel with the osfo as per the instructions. When you're ready to weld in the new panel spray the back side of the patch panel and the inside of the quarter panel (if possible) with the weld through primer. If you can't get the spray in there effectively Spray it on a paper towel or rag and wipe it in. Now you should be able to fit the patch and weld it in place. If you're not too concerned about looks then you can just treat the repaired area with the Osfo and then put a spray coat of rustoleum over it to keep it water tight. I hope this helps. If not, let me know and I'll be more than happy to help you get it taken care of.