Paul, I encountered the same problem on 02650. As everyone said, the only way to do it safely is to remove the fuel tank. (Not too tough of a job). I'll offer this though. The reason the frame rusted there is because by design, it was very difficult for the epoxy to flow to the inside area of the from crossmember. This left the inside walls of the crossmember only partially coated (if at all). Since is rusted from the top down (inside-out), what you have found with hammer is probably only part of what is actually rusting. To be safe, I removed most of that lower plate, prepped and coated the inside of the frame and then welded in the new piece. I have pictures of the entire repair process on my website. (Project Delorean) www.angelfire.com/md2/projectdelorean Go there, go to the "My Delorean" section and check out the January and February entries in the "Frame" section. Also feel free to email me if you have any questions. Steve VIN 2650 "ProjectDelorean" www.angelfire.com/md2/projectdelorean