Has anyone ever smoothed the seam on the rear of the cab, Im wanting to try any tips would be appreciated, thinking of bondo but where do you stop
Bondo will crack and fall out over time. The proper way to do it is to get all of the existing seam sealer out and weld it up. It's much harder than it sounds, that seam sealer is likely hard as a rock after all those years (it was on mine). If you don't get it all out, you will get porous welds (ask me how I know!) and have to do a ton of grinding and re-welding. It's definitely worth doing right though!
Here is mine from when I was working on it. Haven't finished yet (started 2 years ago...sigh).
Take your time and let the welds cool if you go that route. I went a little too fast and warped some of the sheet metal. It's nothing a skim coat of bondo over the top won't fix, but it's just easier to avoid all together. Do a short weld on one side, then a short on the other, and wait a few minutes for it to cool. You will definitely want to use a MIG with .023 wire.
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