If that were mine, it would be scrapped. Even if i could weld or knew someone that could, it would be scrapped. That is a TON of work. Most body shops wont even give you an estimate on something like that. Theyll act as if a skunk just shot them in the face.

 

Here's what you do:

1) Go find a custom sheetmetal shop like the kind that make ductwork for large commercial construction projects. Call up a few mechanical contractors and ask who they use. There's usually a shop in a city which does custom work for contractors (because they can't all afford the machinery or expertise for periodic projects)
2) Call the shop, find out from the secretary who the owner is and when he's usually around, or how you can submit what you're looking for.
3) Put together a detailed hand sketch of what you need, the shape and dimensions and length of each bend. we're talking the straight frame part here. Don't leave any dimension to guesswork. Might as well make drawings of your inner and outer rockers while you're at it and ask for a separate price for them.
4) Either submit the drawing to them, or go to the owner ...wearing your work clothes or some high-viz construction-like clothes (they are used to dealing with contractors not homeowners).
5) Be sincere, get a price for something in the heaviest gauge thickness of metal they can do using galvanized metal. Something like 14 ga would be great. Thicker would be even better if possible.
6) Shops like that which we used to use had bending brakes (the press-style) which were long enough to produce a rail long enough for a Jeep. You might want to make them a little longer or an additional piece if you need rears.
7) Takes them not too long to make one up.
8) I've personally had a shop make long rockers years ago for a vehicle. Took about 15 minutes and in my case they didn't even charge me. It wasn't a big enough job to screw with. I went and bought the crew a $20 box of doughnuts to show appreciation and they liked that.

9) While you're at it, you might want to draw up how inner and outer rockers would look too and have them bend up a set. Just because they can do it in galvanized metal (I don't know if you can buy replacements in galvanized). If you need some extra metal to fill things in, get it from them while you're there so you don't have to hunt around for thicker galvanized metal.

10) Then cut your floors and rusted areas out and weld it all up.

11) If you don't want to go through all that work, just go buy one that isn't so rusty. There's a lot out there. Probably makes better sense.

You could also buy a 4x8 sheet of heavy gauge sheet steel and cut the various peices out you need with a plasma cutter ...and weld them together as needed. That would be cheaper but cost you more time.

 

If you use galvanized metal, the galvanized coating works against good weld flow-out. Best to use a grinder and clean off the coated areas of the galvanized metal prior to welding. The areas you weld on. A flux-core wire process may work better than shielding gas on this process, but either will work.

The fumes coming off welding galvanized metal are toxic. Do out side or well vented area.

Replacing the main frame pieces would be a good project, but not an easy one. If you have good fabricating skills, tools and work area, should be no problem. If not, like others said, may be better to buy a whole new 'clean' Jeep. I'd look at the leaf spring perches too and see what kind of shape they're in. They can also be rebuilt, but if they're gone (which I suspect they are) then you have to consider the totality of the job and if it's worth it.

 

I actually have this exact same crack in the same spot on my XJ. Rest of the Jeep is in great shape but this spot is an issue, especially as it comes to trying to sell it. Did you find anyone who would weld or could help out with your issue?

 

Threads like these as old as they are, make me happy I bought my XJ from South of the "Salt line". Years ago, I went to Milwaukee and saw the mountains of salt there and wondered how long auto frames lasted.

BluegrayXJ, if you have thick skin........take some pics of your XJ frame (I started to say crack, but that read weird) and post them up in a new thread. The guys here are brutal but honest! Basically, you have the options as this OP had. Get waist deep in metal repair or find a less rusted body XJ. It is almost like the rust is alive and needs to spread to live. It is hell to stop and that means cutting it all out and repairing.

 

do this. Start a new thread with pictures

Asking this type of question is pretty much like texting a doctor and saying my leg is broke how can it be fixed? Details and pictures will be needed to decide the best course of action