In the course of restoring an older vehicle, you may need to make a frame repair or two. That was the case with Project Sunny, our Range Rover restoration. We knew even before we took the body off the frame that there were some areas with rust damage. After blasting the frame, a few more showed up as well.
Rusty frames are such a common occurrence in some vehicles that aftermarket repair kits exist. Some even allow you to patch the damage without removing the body, either by welding or bolting overlays in place. There was no such option for the Range Rover, however, short of ordering a new frame. So we decided we’d make the patch panels ourselves.
There was really just one section in need of major repair. It happened to be a short U-section cap that goes over the main box-section frame for rear cargo floor reinforcement. It’s not a significant load-bearing section and contained a perforation only about an inch in diameter.
Given these conditions and knowing that we’re going for a cosmetically correct finish, we decided against making an overlay. Instead, we chose to cut out a rectangular section and butt-weld a repair panel in place. A full MIG seam weld would ensure proper penetration to ensure structural integrity. Below is the process we performed as we prepared the complete frame for refinishing.
Frame Repair Process
Assess the Damage – Determine the extent of the damaged area and mark out further by at least ½ inch to ensure you’ll be welding to solid metal.
Measure and Cut Your Patch – We cut a rectangular section of 0.125” steel about 2.5 inches by 10 inches using a metal-cutting circular saw.
Perform Any Metal Shaping – Our patch panel required a mild arc to be placed into it. We put the blank patch panel into a hydraulic press and gradually worked the correct radius into the bend, confirming with the main chassis for accuracy.
Test Fit and Trim Your Patch – Use a flap disc on an electric grinder to fine-tune the fit of your patch panel. Stitch weld magnets do a great job of holding the panel in its opening.
Clean Debris from Repair Area – Clean up any cutting debris or remaining rust before proceeding.
Tack Weld in Place – Using a MIG welder, tack the patch into place in a few positions to ensure proper alignment.
Stitch Weld – Once you have the initial positioning correct, add more tack welds to close up the gaps. You may also choose to run continuous beads if you’re comfortable you won’t warp or shrink the work.
Grind Welds to Check Your Work – Use a flap disc to grind off excess weld material for a flush surface and to check that you have good weld penetration with minimal gaps between welds. Repair any shortcomings and regrind as needed.
Refinish Your Frame – From here you can apply an epoxy primer or any other direct-to-metal finish.
Nice job. I wish I could post pictures here to show you the repair I did on the rear sub frame section I replaced on my 1965 Dodge Dart. I fabricated several jigs and made numerous measurements against a factory frame chart. The splice cut between the two bolt holes for the axle snubber. When it was done I was able to screw in the bolts through the snubber by hand. The welds were invisible after grinding and dressing the metal.
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