|$15 at Harbor Freight|
Clear Your Paths
Under the right (passenger in the US) side floor, there are small pipes and cables that you don't want to set your cutoff wheel into. These pipes and cables are held to the floor underside with nuts and brackets, and further held into place with some rubber bits. Remove the nuts and the brackets and pull the rubber bits out. Toss all of it into a ziplock and mark it as part of the right floor. You'll want them later. Let the cables and pipes hang as far out of the way as possible. Among these is the fuel feed line, the vapor line and the main power supply from the battery. All super important.
|blue tape the cut lines|
Mark the Spot
Before you grab your grinder, you need to find the frame sections underneath. On the right (passenger) side, I followed instructions I found online, where I drilled holes at the corners of various support structures. I then connected those dots with blue painters tape and then drew on those lines with a sharpie so I had clear lines to follow. This did work, but for the left (driver in the US) side, I thought I could do it with fewer steps. The first step is the same: with one had under the car and the other resting on the top of the floor, tap with your bottom hand at the corners of the beams. Feel for the tapping with your top hand, and keep circling in on the spot by tapping until you know exactly where the spot is. Mark it with a sharpie. On the right side, I drilled a hole. On the left, I just marked it and moved on. I ultimately found that the drilling was unnecessary. There are 2 main under-floor rails, one runs from the transmission hump to the edge under the front seat mounts. The other runs from that cross rail between the legs to the front. In the US model, imagine a rail running straight at the brake pedal. These rails are about 2 inches wide, but there is only about 1/2" lip that it spot-welded to.
Measure Twice, Cut Once
This phrase has been made famous by arm-chair trades-persons dating back to the stone cutters in Egypt. Still, its a good practice. Double check your marked lines to make sure that you didn't draw a line through a section of frame. Also consider if your cut-path will send you through any of the cables or pipes you moved aside earlier. Cutting through a fuel line, even if it's empty, really sucks. Yes, I did and I'll explain how I fixed it later. Along the rear edge, there are two heavier sections in the corners that are not to be cut out. They create structural stability and should only be removed it they are not doing that job. My bar had a pretty rusty floor, but those sections were fine. Make sure your cut lines take these sections into account.
The Fun Part
The floor is cut out in 3 or 4 sections, separated by the frame rails. Cut the rear out first. The rear section comes out as one large, nearly square piece, and the steel cuts pretty quickly once you get started. With the rear cut and pulled out of the way, you can see the cable, etc on the right side. Next, I cut the outer of the two forward sections. Again, this allowed me to avoid the cables, etc on the right (passenger) side. Last, I cut the inner section, and it was all pretty clean except I nicked the fuel line for about an inch, leaving a nice gash in the metal fuel line. At this point, I was glad I'd pulled the fuel tank, and let the system sit for a week or so.
|spot weld cutter|
Hit Harbor Freight and buy at least 2 spot-weld cutting bits. They are small, fit in your drill, like a regular drill bit, but they are designed to cut spot welds. The shiny, silver point in the center of the bit is set into the center of the weld, and then you run the drill at a slow speed to cut the sheet metal around the weld. This allows the rest of the sheet metal to rise from the rail. Each bit is reverse-able, so as you burn out the teeth, you can pop it into a vice, loosen it with a 1/4" spanner, flip the bit and tighten. One bit lasts twice as long... which still isn't that long if you run your drill too fast.
So, now that you understand the weld-cutter, slap a grinding wheel or wire wheel onto your grinder and grind on the remaining bits of floor so you can find the spot welds. Between rust, paint and black-tar seam-sealer, you may have to grind a bit to find the spot welds. If you can't find them all or you don't want to grind to find them, there is an alternative; you just need to be willing to use a framing hammer and chisel.
The Not-So-Fun Part
As you remove flooring, the remnant will start to flop around. On my first (right/passenger) side, I just crumpled the metal out of my way. While this worked, I found that by cutting strips in straight sections (using tin snips) was more effective. And, ff you set them aside with the larger sections of floor you cut out, you can re-create the shape of the floor later.
Clean It Up
|temporary protective paint|
Since I was not going to be working on the project for a while, I shot the cleaned up space (including the rails) with primer and some orange Rustoleum so I wouldn't have new rust appear while I was away. This meant I got to grind that paint off later, but if you're not going to jump right into welding, I'd encourage you to consider the same.
That's it for today. More next time. Thanks, as always, for following along-