Floor Pan Replacement (revisited)

Q: Floor Pan Replacement (revisited)

I have just found that I need to replace the passenger side front floor in my 68 and wondered if anyone had any experience with this procedure. It looks as though I must remove the seat attachment structure then go at the floor after that is removed. My question is what type of tool is best suited to break the spot welds and other weldments? Cold chisel? Small explosive charge? Any words of wisdom would be greatly appreciated…Oh, also I have a weld pak 100 flux core welder would that work for the welding?

A: I know there will be others responding to this question…. and I believe there is more than one way to perform this task. First off, if it is a convert, then you have more chances of twisting things out of place. I’m about 75% done with doing total floor pan reconstruction on both sides on my convert. I have taken an excessive and some would say obsessive amount of time in doing mine, but then I’m trying to make mine look close to factory both inside and out. My only advice to you is to support the vehicle carefully and with equal pressure on both sides. Consider welding in temporary braces if you have any doubts. I did not, but mine is just a shell and I have very carefully supported the shell in critical points. That may not be proper for your situation.

Go slowly, AND PLEASE… CAREFULLY, mark the alignment of the seat support and frame brace before you remove them. Measuring afterwards is very difficult. Cut carefully and plan on it taking longer than you thought. As far as cutting goes, use a good spot weld cutter on the seat support brace and frame brace (underneath the seat support brace). Use an air chisel on parts of the old floor pan that you want to rip to shreds and be careful not to damage anything else with the air chisel. Once the floor is out, clean everything up carefully and get all of the rust off of the braces and rockers before repainting and re-welding. ONE BIG CONSIDERATION…..

Examine the front floor board supports carefully. Mine were really bad due to rust. I had to remove them, reconstruct them with heavy gauge steel and reweld them in. It was really time consuming, but I won’t have to worry about doing it again.

A: You’ve already received a lot of good advice so I won’t put you through a lot of details, just some details.

If your planning on removing the seat pedestal, keep in mind the damage your going to do the existing floor pan. The spot welds run across the front, sides and back and as mentioned, there are also a couple you can only get to from the bottom unless you disassemble the pedestal (which I don’t recommend). Even if you only need – of the floor pan, consider buying the whole unit. This will give you enough metal to repair any damage cause by the seat pedestal removal.

When you purchase your replacement pan, be aware that most replacement pans have the lip on the rocker panel side folded “up” te make welding easier. If you are doing a partial pan and you have to repair the rocker area, you’ll want a pan that folds “down” to match the original. I’ve only seen these sold by a company called C.A.R.S. Inc. (714-525-1956 California or 248-398-7100 Michigan: www.carsinc.com)

I just finished replacing my third set of floors. The easiest way I’ve found to remove them is to drill the spot welds along of the top rocker panel then just cut the pan across the front, back, and tunnel. This will allow you to easily remove the pedestal from the car. Then just separate the old floor pan rom the pedestal. The replacement pan is designed to cover the area above the pedestal so repair is easy. The replacement bent to match the original bends so really, the pedestal can only go back to it’s original location. Plus, the spot welds on the rocker side will act as and additional locator point.

Mock fit the panel in it’s final location and set the pedestal in place BEFORE welding. Use self taping sheet metal screws to hold it secure while fitting but pre-drill the outer layer (usually the replacement panel) first.

Q2: I found your advise about removing the pedestal with the pan to be sound. Although I have not removed the floor yet I am planning on doing it as you described. If I might pose a few questions: along the front, back, tunnel side, and rocker to what elevation or point do I cut? Along the front I see the over lap, do I cut such that the overlap is removed? Rocker side: I have the turned down replacement pan I purchased at Classic Ind., seems to be perfect match, Do I drill out the spot welds along the flange underneath the car where the two meet? Looks like that might be the spot. Finally, along the back of the pedestal how far behind it can I cut? Directly at the termination of the pedestal rear sheet metal?

I really appreciate this site and all who contribute! I could reinvent the wheel or I could just ask you all to help. And you do very much thanks again

A: The cut along the front depends on two things, the length of your replacement pan and the amount of cancer. If you have a full length pan that extends up the kick board then you can remove all the metal up to the top of the pan.

As far as the seam, a full length pan will cover this area. The full pan only mimics what was originally two pieces. The thing to look for in this area is the lower firewall extends under the toe kick. I usually cut around this piece and lay the new pan over the top of it. This way you can’t get the pan too low. You may have to trib. your pan on the rocker side or open the pinch weld at this point because the pan is originally sandwiched between the lower firewall and the rocker.

I would not try to remove the spot welds along the bottom of the rocker. Instead, I would use a air chisel on the bottom side along the 90 degree bend. I usually start at the front and rip the old floor front to back. When the old floor is removed, hammer the edge of the old floor flat against the edge of the inner rocker. When you go to install the new pan, pre-drill the lip of the pan to mimic the spot welds along the bottom edge where it will attach to the inner rocker panel and weld.

As far as how far to cut behind the seat pedestal, again it depends on how much new metal you’ve purchased. If it is just a partial pan, find a couple of common points to measure. If your new pan has a pre-drilled hole where the rear sub-frame bolts enters, use this point and compare it to the original. If this hole is not there, look at the tunnel side and note the slight bend. This should also be evident on the new pan and is also a good reference point.

As far as the elevation of your cuts, once you remove your seat pedestal, lay the new pan in place and trace a line around the whole thing then, DON’T CUT ABOVE THIS LINE.

Hope all this helps. Let us know if you have more questions,

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