I removed the fender, bumper and bumper mount to repair the rust damage under the battery. I notice the bumper mount has been holding a lot of wet dirt between the frame rail. This caused rust to eat away more of the fender apron than I expected. When it goes back together I will fill this void with seam sealer to keep the dirt out. I made a single patch panel from 18 gauge sheet metal to cover both apron and battery table. To bend the sheet metal, I clamped it between a piece of angle iron and my work bench using C clamps. The patch changed from a 45° to 90° about half way across above the frame rail where the battery tray bolt hole is located. I decided to use the original metal from this hole back to the shock tower. Using a cut-off wheel on my angle grinder I cut about five relief slits about 3" long on the patch where the battery tray bolt hole is and tapped the metal closed with a hammer to fit this angle. I then mig weld the cuts.
I patched the big holes in the shock tower that someone cut to grease the control arm. Why they cut them this big is a mystery to me. After grinding the welds I put 2 coats of Rust Bullet and re seal the seams with seam sealer. The next day I painted 2 coats of bed liner. I bought a new '67-'70 Mustang battery tray and drilled the spot welds from the bracket and welded my old mount to the new tray. The reinforcement plate is from a '68 Mustang