Floor pan or cab corner first?

[Mustard72]

I'm working on replacing the cab floor in my 72 C20. I've got the cab off and on its back and the floor removed. The bottom of the back wall of the cab (where the original floor was spot welded on) was rotten. The cab corners were also pretty rough, as were the bottoms of the back pillars. I could keep going on what all was rotten, but probably shouldn't (lol).

Should I replace the cab corners/pillars before or after replacing the floor? I need to weld new steel in for the bottom of the rear cab wall anyway, and figured it made sense to simply put this piece in between the new cab corners to line it up. Whatever I do, I need to weld in some steel for the back of the cab floor to be welded too.

My old floor was not "attached", so to speak, to the rear wall of the cab (yep, it was pretty bad back there). How should I go about vertically positioning the floor on the back wall prior to welding it into position? I don't really have any original measurement to use.

Thanks for any suggestions.

[Mustard72]

By the way, you can see pics of what I'm dealing with in my build thread (see my signature).

[sduckworth13]

Not 100% real sure, but when I did a similar repair, I did the floor section first and the cab corner last. I just wanted to say, I used the Tabco cab corners and by far the best fitting cab corner that I've tried. How's your rear outer cab support look? You might want cut some rust off it and repair it since your going to have the floor section cut out, I mention that because the floor section is spot welded to the cab support and just easier to replace it while your there.

[Mustard72]

Hey, thanks for the reply. I've sort of started going down the path of replacing the cab corners first, though. The bottom of the back wall of the cab was pretty rotten (where the new floor will need to connect), so I figured getting the cab corners on would allow me to properly position the patch I'm making to go between the cab corners along the back wall of the cab.

I can only imagine how nice the Tabco corners fit. My LMC ones definitely need some tweaking to get the right bend around the corner. But they have a really nice catalog...

I'm replacing the entire floor with the floor assembly from LMC. This includes the rear outer cab supports. My originals were very bad. The front outer cab supports were almost non-existant. Thanks for the suggestion, though.

So at this point I'm just going very slowly and carefully to make sure it all goes together the way it should. I'm a little concerned that, with the amount of stuff I'm replacing back there, that if I do the cab corners, etc. first, the span between the sides of the rear pillars might not match up correctly with the floor. But I'm going to set the floor in place a few times (lots of fun with one fella doing the lifting) to make sure it all looks right before getting too crazy with Mr. Welder.

[sduckworth13]

Alot of guys from the post I read of guys doing a similar repair, brace everything up by spot welding bars to brace everything up on the inside of the cab so nothing moves. There are several threads on the subject here on the forum. Good luck with your project.
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[turp mcspray]

I would fit everything together, before welding anything solid. Either attach the parts with screws, vice grips, or tack weld them. That includes bolting the doors back on. Then if something doesn't fit, (and the chance of something not fitting quite right, is FAR greater than everything fitting perfect) you can make some adjustments by either moving something a little, or cutting and slicing if need be. It is much easier to remove a screw or vice grip, than it is to cut something back out.

[sduckworth13]

Sorry didn't mean spot weld, tack weld the braces. Thanks Terp for the correction.
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[turp mcspray]

I was just referring to the parts, not correcting you in any way. Sorry if it sounded like it.

[Mustard72]

OK. Thanks for the input. I've seen the screws method used, which seems like a pretty good idea, especially seeing as though I don't have all that many sets of vice grips or clamps that would work. Screws are cheaper than more tools

Thanks again.

[Mustard72]

Well, I was hoping to make some serious headway over the weekend. I had one of the cab corners tacked (albeit "heavily" tacked) in before, but I didn't like how the floor fit with it in there, so I ended up cutting the cab corner back out. I was going to try and get the bottoms of the front door pillars replaced, too, but ended up not proceeding with that, either because I wasn't sure how to get it lined up with the floor, which wasn't in. I did some more research on this site and found a good build thread with some decent pics showing the floor going in before anything else, although his front pillars were re-useable. Haven't been able to find a rebuild thread with pics for a cab as bad as mine, yet. I'm sure somebody has done one, I just can't find it.

So, I'm going to do the floor first. It seems obvious at this point to get the floor in place and build from there, so I'm back to making progress again rather than standing there staring at the dang cab.

[bobcat1]

how did you end up locating the floor height? I am in the same situation , rear cab corners gone and front "a "pillar are gone, any help you can provide ?