XJ - Ass Cancer Rehab Part 2: Bending a New Passenger Frame Rail

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Using a metal brake to bend up new frame rails wasn’t my plan A. Nor was it plan B. It was actually plan C. I was trying to fix my Jeep on the cheap because this repair wasn’t suppose to happen till spring. That meant no buying extra tools and trying to make do with what I had.

Plan A

The first plan was to cut up some spare 2x2 steel tubing for the 90 degree bends and then weld them with pieces of sheet metal to create new frame sections. It’d take a lot of cutting and welding, but after grinding down the welds it’d be hard to tell how they were made.

The plan sounded perfect and I was gung ho right up until I tried to do it. I couldn’t make a straight cut with the angle grinder even if my life depended on it. I was working on the floor of my shop and with no bench vise nearby it was incredibly difficult to safely hold the 2x2 tubing in place while cutting with the angle grinder at the same time. Not wanting to risk losing a finger I had to throw in the towel and go back to the drawing board.

Plan B

Realizing I couldn’t make great cuts working on the floor I thought my next best idea would be to buy rectangular tubing already in the size I needed and cut them into sections and weld them together. Basically making a “frame”.

Well turns out they don’t make 2.5"x4.5" steel tubing. The closest you can get is 3"x4" tubing. After spending some time with a tape measure under my XJ I determined 3"x4" would in fact work. There was just enough space between all of the suspension components and the gas tank would still be able to fit between the rails.

Excited that I was on to something I took a trip to my local steel distributor (having recently learned that’s the best place to buy steel from) and picked up some 3x4 tubing.

Unfortunately this is where the plan went sour. A few days earlier when talking with another steel distributor (who was the one that broke the news to me that steel only comes in certain sizes) he mentioned I should go with 3/16" steel so it would be tougher than the factory stuff. Having never dealt with steel thicker than 1/16" inch I figured it wouldn’t be that tough to handle since it was only 3 times as thick. Boy was I wrong.

3/16" steel is some thick stuff. So thick that it doesn’t flex, nor is it easy to cut. That stuff is heavy. On top of that my little mig welder can’t even handle 3/16". Plan B flopped harder than plan A and actually costed me some money.

Plan C

Freaking out at this point due to having wasted a valuable week of time and making no headway with a Jeep stuck on jackstands, I realized I had no other choice but to go and buy a metal brake. A quick peruse of Craigslist revealed good metal brakes go for about $700 if you’re lucky to snag a deal.

Not wanting to spend that much change if I could help it, I did a bit more digging and stumbled across the Harbor Freight 36" metal brake for $207 and some change after applying a coupon. The reviews on it were good, and after a few mods it could make a pretty decent bend on 16ga.

A few days later my new brake arrived.

The first thing I did was weld on 1/4" plates to act as braces on the sides, and added some 3/16" tubing on the back to allow for an additional bolt to be used on each side for holding down the clamping portion.

It’s two tone because I only had black spray paint laying around.

After that I welded on some handles since the ones that it came with were a joke and less than 6" long. I also added a brace directly above the handles to strengthen the bending blade as it’s known to warp when bending thicker metal and that can mess up your bends

The last mod I did was add a small crossmember to the front of the stand that gives you something to put a foot on so you can hold it down from flipping over when bending metal.

(If you plan on replicating my mods check out this video that I used as inspiration.)

With the brake modded up it was time to get down to business. A couple of practice bends later I had the brake dialed down pretty nicely. I even adjusted it to soften up the bends a hair to make them more rounded like the edges on the Jeeps frame.

I had to bend the rail sections in two halves. The brake gets in the way if you try to bend them in one go.

Each frame half is made by making a 90 degree bend at 1". Then remove the sheet and flip it around so the bend is now pointing the other way and put it back in the brake. Measure 4 1/2" out and put another 90 degree bend. Finally remove the sheet and cut 1 1/4" in from the last bend.

By leaving 1 1/4" after the last bend it’ll make the frame 2 1/2" wide when the halves are joined. The new frame piece will be slightly taller by about 1/16" than the factory one, but I found this to be fine.

Some welding and grinding later and you can’t even tell.

Don’t weld too fast or else you’ll warp the piece. I found the best way to weld these up was to lay 1 - 2" long beads at a time. Try to space them out so the halves are welded evenly instead of starting at one end and working to the other.

The initial frame sections I made were 24" long since I was starting with 24"x48" sheets of 16ga. I made a few 24" runs and then chopped them up into smaller sections to make my rails.

I figured out the frame rails directly below the cargo area of the floor could be recreated with just 3 sections of the following lengths: 10 1/2", 7 1/4", and 15".

There’s a slight angle between them as the rails get closer to each other as they move towards the front of the vehicle.

Inside shot. Most of that is penetration but I did lay a few welds from the inside on some spots that looked cold.

From there I made a second frame piece for the driver side that I set aside for later use.

With a portion of the frame ready for test fitting I needed to remove the old one. There’s a ton of spot welds you’ll have to drill out. The majority of them are on the floor.

I was using one of those cheap spot weld drill bits to remove mine. Buy it off Amazon or Ebay if you can as you’ll get a lot more of the cutting blades than if you buy them from a store. You’ll want spares as they can break a tooth or snap pretty easily.

Run the drill slower than you would with a normal drill bit. I’ve found a slower RPM will actually cut faster.

Then one cut with the angle grinder later that left me feeling uncomfortable that I’d be able to fix this we finally had the room to do some test fitting.

The flat part of the frame tested out good so I bite the bullet and cut even further into the Jeep.

Below the rear seat is where things get tricky. The frame bends in two spots while at the same time changes in not only height but width too.

At the rear of the Jeep the frame is 2.5"x4.5" (skinny and tall), but at the front of the Jeep it’s 3.5"x4" (short and fat).

It took me roughly 12 hours from start to finish to recreate this piece of the frame since I wanted to do it in as few pieces as possible. If I remember correctly, it’s 19" long.

I made the initial piece using two halves that were welded together. From there I made some cuts where I needed it to bend and welded in pie cuts.

The pieces of metal tack welded on the top are braces that were used to prevent warpage during welding. I made two of these but one was ruined from welding too fast and warping the piece.

Lots of test fitting later I was able to build the complete frame rail.

Mocked into position and held up with vise grips.

You can see where I welded in patches on the floor last winter because I cut holes in floor to get at the upper shock nuts that rusted out.

Before I could weld in the passenger frame rail I had to do a few extra steps. For one, the seat belts of the rear seat tie into the frame via a little bracket on each side. Mine was rusted out and not wanting to weld on a rusty piece to my new frame I ended up sandblast it, and replaced a portion of it.

I notched the frame a bit so the seat belt bolt bracket would fit snug in place.

After that the frame rail was sandblasted and sprayed with SPI epoxy primer. I didn’t go too crazy grinding welds because I plan on welding on frame stiffeners so they’ll hide any imperfections.

It was almost time to weld in my new frame rail, but first I needed to tend to some rust issues on the inner wheel well on the passenger side. There was still a small lip of the old floor left on the wheel well that needed to be removed as I could see rust growing from inside the seam.

After removing the lip a wire wheel was used to remove the rust.

There was something wrong with the little bracket that the upper half of the rear seat pivots on.

It was mounted in the correct spot, and operated fine. But when looking inside the wheel well from outside of the vehicle I saw rust breaking through the undercoating.

Figuring I may as well address the issue while I had the floor out I chopped out the rusted metal and welded in a patch.

I made the patch longer than necessary so it went all the way down to the bottom that way I’d only have to weld 3 sides. A flap disc on the angle grinder was used to contour the bottom edge.

New braces were made for the seat pivot bracket as well. These are made from 1/8" steel. These go on the inside of the wheel well directly behind the pivot bracket. I forgot to snag a picture of them welded in place.

Painted up the wheel well.

Inside too. The inside of the wheel wells will be painted with bed liner at the end to hide my work.

And while I had some paint in the gun I sprayed my seat belt bracket.

A day later a couple other brackets were sprayed. The 3 brackets on the left were modified after painting due to design problems lol.

With everything painted up I finally welded in the frame rail. If you look close you’ll see nuts for the bumper mounts were welded in as well. The nuts are M10x1.5 flange nuts.

I also welded back in the seat pivot bracket.

This is what remains of one of those brackets I said was modified earlier. They interfered with the shackle brackets so I had to improvise.

Test fitting the frame tie ins for the rear bumper. I bought these since I’ll be installing a DIY aftermarket steel bumper that has a hitch receiver built into it.

Don’t mind the paint blemish. I purposely went a little extra heavy spraying paint inside the frame rail since I knew no one would ever see it once she’s all buttoned back up and I wanted to be sure I got a good coating on the inside to prevent rust.

It’s exciting to be able to use off the shelf parts with my work.

With one frame rail complete I finally felt more confident in my ability to fix the Jeep. There was multiple days during this repair where I really questioned if the Jeep would survive this. I was feeling slightly relieved but at the same time dreading having to repeat all that hard work plus more for the other side.