Sir, Suggest using dremel steel cutting disc to sheer off nuts/bolt if force applied doesn't unbolt them readily. Then you will need to weld new sheet metal underneath with bolt pockets within. For the fenders you will need to find metal replacements if they are so far gone that you can't weld new underneath metal lips. Mine were too far gone and I ended up finding 2 practically NOS for $1875.00 including the shipping from KS. V/R, Nick Cavallaro, Bel Air, MD
