1961 Chevy Suburban Floor Install - First Time Floors

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Vintage trucks aren’t known for having had a pampered life. They were utility vehicles built for work and abuse, and that’s exactly what they got--along with a healthy dose of neglect along the way.
Part of their utilitarian nature was a rubber floor mat in the cab. Durable (for a decade, anyway), the rubber mats repelled mud and water, and made cleanup easier (if the owner was ever so inclined); but they also trapped moisture between it and the sheetmetal floor. So in addition to the normal rust from 50 years, old trucks got a double-dose and rusted from the top down. By the time we get ’em, it’s a pretty safe bet they need new floors.

The beauty of welding in new floors is that they are the perfect job for the beginner with minimal sheetmetal and bodywork skills. Processwise, it’s a simple matter of methodically removing the rusted panel and fitting the replacements. The skill builder is in the welding and finishing.
The standard beginner method of installing patch panels is to cut away the rust until you hit solid metal, make a stepped flange (usually with a pneumatic panel flanging tool), trim the replacement panel to fit, lay it on the flange, and weld it. The overlap is then covered with body filler. This method works, but there’s a lot of area for moisture to get in and cause rust, and the repair is always visible from behind. This may not be a big deal on a floor or firewall, but you’ll see it on the back side of your hood or bedsides.

The proper way to weld replacement panels is a butt-weld. The problem with butt-welding is it’s extremely time consuming, and it’s real easy to end up with heat warping, though heat warp doesn’t tell the whole story. The key is getting the gap right between the two panels; if the gap is too big, you’ll have to add a lot of filler wire (and heat); if the gap is too small, as the heat is applied and the metal expands, the adjoining edges hit each other and will buckle the metal.

Trimming the metal to fit perfectly is tricky business. A shortcut is to secure the panels together and slice through both at the same time with a cutoff wheel, creating a uniform, matching seam. All cutoff wheels, however, are not created equal. The proper gap between panels to be butt-welded is 132 inch, and though most thin cutoff wheels are labeled as being 132-inch thick, we’ve measured them at two and three times fatter. We use Lawson wheels (PN 93483), and while they’re more expensive than the hardware store wheels, and they’re just a tick fat, they’re the thinnest we’ve found. Don’t scrimp on cutoff wheels--good ones will also last longer, so you’ll buy fewer of them. Another key to good results is "easy grind" welding wire. It’s also more expensive than standard mild-steel MIG wire, but it’s much easier to work, and doesn’t leave a brittle weld. Finally, and we can’t stress this enough, take your time. Metal master Ron Covell once told us to always make sure you’re in a comfortable position when you work, because it will allow you to take your time and be fussy. We rushed a couple of areas, and ended up with sloppy cuts and some sloppy welds. After we slowed things down, the work went much smoother--and much quicker!

Our project is a ’61 Chevy Suburban. While the replacement panels extended into the wire channel/top of the inner rocker, our rockers are solid so we only replaced what was needed. And that’s probably the final tip: When you buy a replacement panel, don’t feel like you aren’t getting your money’s worth if you don’t use the whole thing. Buy a panel for the contours you need, and use as little as possible.

Our method here is straightforward, but time consuming. And while they’re "just floors" and would have taken less than half the time had we lap-welded, we use it as an exercise toward building our skills so when it’s time to do fender repairs or doorskins--where fit and finish really matter--we’ll have better results. At this point, our process isn’t bad, but we need to dial in our welding a bit. With a couple of these installs under our belt now, we’d hesitantly tackle a fender or hood; before the floors, we wouldn’t have considered exterior panels something within our abilities. And that’s why a floor job is the perfect beginner project. CT



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