Creedmore

My xj frame is rusted out on pass side rear need ideas or help on how to fix it

fb97xj1

Thats not an easy fix, nor is it going to be cheap. If you cant weld, scrap it. One hard hit in the rear and thats going to buckle like tin foil. You are better off finding a donor and swapping the good stuff over to it.

Do NOT drive that.

PatHenry

That is extensive - I'll second what fb97xj1 said - don't drive that!

If you're dead set on fixing it, you need to take it (i.e. tow it) to a frame specialist. If you're anywhere near central MA, I can recommend a good one. However, as noted, you're easily looking at $1000+ to get it safe to drive.

Creedmore

I can weld just seeing if anyway possible to build a new rail to put in on that side. The rest of the frame is solid that's the only bad spot on the frame been driving for a year like that

dmill89

Of course it is possible, the easiest thing would probably to get the section of rail from a donor vehicle (though if you live where rust is common it might be hard to find a "good" one in a Junkyard and if you're going through this much effort you want a completely rust-free section not just one that is better than yours, if you start with a rusted section you'll likely be back in same spot in a few years). If this isn't an option you can build one out for U-Channel and plate (the spot where it "arches up" in front of the axle will be a bit tricky), but note if you go this route you are removing part of the crumple-zone in that part of the vehicle and it won't absorb as much energy in an accident (but still better than a rusted-out rail that will crumple like tin-foil).

Creedmore

I got a big sheet of 1/8 steel plate I was thinking about taking it and cutting it to the pieces I needed and making it where it would go up in side of the rail and welding it in then taking some these frame stiffeners I got from hd off-road and weld over top of it all would that work?

00t444e

I had some rust in the same area but not as bad. I had a buddy of mine weld in a piece of 3/16 steel C and it has held up fine.

Martlor13

but see, if you dont clean that rust up its just going to spread. You cant just cover it up...and i think when you start cleaning it up, more and more of the frame is coming off in pieces., making the job even bigger.

Walker Lilly

Creedmore

What bout do something like this seen in another form

BlueRidgeMark

I had exactly that problem. I cut out the rail from a 94 I was scrapping, and welded it into my 97. Did that last summer, and it was fine. Not the prettiest welding, but it held up fine.

Where I butted the sections together, in the new section, before I put it in place, I welded some plates of 1/8" steel sticking out to support the joint. This gave me a very solid backing for the weld, for most of the joint. This turned out to be absolutely essential, because the perfect but joint I had pictured in my mind didn't turn out that way. I had a big gap. With the plates, this was no problem. I had strong metal bridging the gap, and I was able to weld across it.


Because the rail is radiused at the bottom, and flares out at the top, I could not get the reinforcement plates to fit the side walls and bottom of the rail exactly, but I covered as much of it as I could. See the diagrams:


End view (frame rail cross section)

The blue is the rail, the black is the 1/8" steel plates. You can see that I didn't get down into the corners with the plates, but most of the sides and the bottom of the rail are covered. I welded them in from the inside, and I also drilled a couple of 3/8" holes in the rail for each plate and did rosettes.

I did rosettes on the 'new' frame rail going in, and on the old frame rail.

The only other tricky part is where the rail intersects the cross-frame member where the shocks attach. What I planned was to leave that completely intact, cutting the rusted frame away from it on the good vehicle, and cutting it away from the donor frame on the donor vehicle.

I found I needed to cut it a few inches back, and butt weld using the reinforcements like I did on the rail. This is because the cross member is installed after the frame rail, and so there is a lip of frame rail underneath the cross member. It was either completely remove the cross member, and then put it back, or cut the cross member and re-weld it. I cut it.

The rest was pretty straightforward. Drilling out spot welds and rebuilding them. There's a bit of trickery with where the bumper mounts, but it's not a huge deal. I forget the details.

I did cheat a bit, though. Some of he spot welds matched up perfectly, or very close, between the donor rail and the donee Jeep. Some did not. For the ones that did line up, I inserted 1" 1/4-20 bolts and bolted them together. This helped a lot in lining things up correctly. That lining things up really is the biggest challenge. Once I had it lined up and tightened into place, I welded the rest. Some places I welded from underneath, some from above. (You will need to remove all of your interior upholstery back there!) I used a cheapo Harbor Freight copper welding spoon to back up welds where needed. Once that was all done, I pulled the bolts and welded up the holes. (Except for a few that gave me a hard time. They got sealed and left in place.)

It was a lot of labor, but not much out of pocket cost. Some wire, some grinding wheels, some bolts. Oh, and I paid 50 bucks to have the new rail sandblasted and primered before I put it in place.


Bolts and welds.


Cross member cut back, showing where the frame rail lip goes under it (which is really on top of it, but you get the idea).


In progress, shows the good rail end. Cleanup here was difficult. Hard to get tools in to work. A vibrating cutter might have helped.


Almost ready for new rail.


Bolted in place.


Oh, ugly! Big gaps at the butt joint. Reinforcing plates are clearly seen.


Big gaps. See why the plates?


Inside the rail to reinforce where the cross member welds back into place.

Creedmore

Thanks blueridgemark gonna try what you did i been driving my Jeep for a year like it is

BlueRidgeMark

By the way, drilling out the spot welds is made a lot easier by using the right tool. I used one of , but mine was from Eastwood. I see they don't carry them anymore.

Instead, they have these.

What's the difference? The one I used has a spring-loaded pointed center guide. It slipped a lot, which usually broke the cutter bit.

The better choice has a real pilot bit, which will drill in and then can't slip once the cutter bit starts cutting. If I were doing a similar project, I'd spend the money to buy the kind with the real pilot bit.

Creedmore

Ok thank you I'm gonna try and go to the junk yard this weekend to pull that piece frame off

BlueRidgeMark

You'll need power available, or a wagonload of batteries. That's a lot of drilling and cutting.



Let us know how it goes!