Will the frame shift if i remove/cut the rear crossmember out ?

[candymancan]

My rear cross member on the J10 is swiss chease litterally. I never fixed it due to being unable to find a c channle replacement.

But an old thread on this forum showed a YJ front bumper will fit. Same thickness too.

I got one today from the jy for 10$ lol. And holding it up to the old cross memver it is the same size.. it looks like.

So i have to unbolt my bed and lift it at least a foot so i can get to the cross memver.. and cut it off the frame. Ill have to rebuild the last 3 inchs of frame on that back as well its all gone basically.

So yea if i cut it off will the frame move ? Or will it stay in position back there. These are pics from like 7 months ago but its still the same today as i never touched it.

The next cross member abive the axle is kinda far away.. so i worry itll shift.

Maybe i should weld a t post or somrthing temporaliy between the rails near the cross memver so it doesnt move ?

[sierrablue]

As long as you're not jumping on it or anything I would think it should be fine, especially if you keep it marked.

These frames also don't really have much/any diagonal support and will move around some anyway. If you're really worried about it I'd start the process with the bed still on it to keep it at least close. Or find a way to keep the rusty stuff in there and just add onto it, then maybe cut out the rusty stuff.

[Stuka]

Just tack weld something in place across the top of the frame a little ways in front of it. Its easy insurance to make sure the new rear crossmember isn't changing the width of the frame rails. Because it would suck to find out the bed mounts no longer match up.

[candymancan]

Yea that what i was thinking of doing thx

[Srdayflyer]

absolutely tack weld a temp member in place, the tsm shows the frame dimensions to double check things when doing the repair

[threepiece]

I have replaced several rear members in the past. It is not necessary to stabilize the frame prior to cutting. The frame rails can be easily moved in or out with a ratchet strap or jack respectively. What is important is replacing the same distance between the rails. Taking a measurement or two prior to cutting would be prudent.

There is square structural tubing available that works well for FSJ’s. I can’t recall for certain what size but I believe it is 4.5” square and definitely 1/4” wall. It is somewhat unusual size and may be special order only.

One tube of correct length will make two X Members after it is ripped down the middle, a task not suited for everyone. The parted halves will subsequently be warped. Further processing in a press or the like will be needed.

[rocklaurence]

Correct, just make sure that the frame is level and square when attaching the new X-member

[candymancan]

Well you were right..frame didnt move. Cept a tad on the bottom it twisted outward. Used a strap to pull it inward a little.

The thing that did move was the bed itself. Which dropped down a little. I had to jack both corners of the last bed cross member (which sits above this frame cross member) up to keep it level.

Bolted the new frame cross memeber to the bed first to line it up good.

Then welded it on. I welded both sides.. meaning inside and outside. Top and bottom of both lips on the c channle.

I dont THINK ill need a fish plate with welds like this.. even though its vetical welds. But what do you guys think ? I do plan to do some light towing with this bumper. Nothing like 5k+ lbs. But a small trailer with lawn equipment etc.

I think itll be fine. Ive done similar welding like this to my wagoneer and it pulled my J10 with flat bed at 6400lbs just fine.

I injured myself though.

When taking the old one off.. i left a hair of metal on it and thr bolts.. so it wouldnt fall on my face. And i then un bolted it and backed away to pry on it to get it off.. my other hand though, stupid me was in the way and the old cross member fell on my middle finger.. and sliced me open good. Two spots.. blood everywhere.. deep cut.

But i cleaned it up and bandaged it and kept going.. the hospital out in the country where i live is 1 star rated.. and the urgent care clinic was closed..

So if i can bend my finger and move it around.. i think its fine.. it needs stitches though.. so maybe tomorrow ill go to urgent care.

Anyway here it is.. and you can see how bad my old one really was

[rocklaurence]

Years ago I purchased the "Ugly Truck" and the rear X-members was pulled out into a U shape by the previous owner. Probably using the X-member as a tie point for retrieval. So, I cut it out and replaced it with a 6x2x3/16" tube. I also integrated a receiver tube into it. Worked out great and was better than OEM.

[candymancan]

well update on my finger, the old cross member broke it, and i got 4 stitches lol. Damn, well i did manage to weld thee new one on with that broken finger bleeding all over in my bandaid that night... Went to urgent care today.. Had to get stitchs and a splint.. haha

Damn, first major injury on a Jeep.

Anyway, do you guys recomend i fish plate this ? Im not sure if the sheer force and downward force on the frame right here will need a fish plate. I know for a fact that Vertical welds are just as strong as Z cuts and welds.. Which couldnt be done here due to the leaf spring mount on the other side.. It had to be cut and welded vertical.

But with this entire section seeing all the weeight of the bumper/hitch combo and say a trailer. I would assume that most of the force on this peice would be the top of the c channle with tongue weight and stuff on it.

Was thinking of welding a plate on top of the frame C channle between the two peices at least.

[letank]

Good news on the finger, what a drag!

Get some steri-strip in your first aid kit, they are as good as stitches until proper care. Then you can cut off one finger of a disposable gloves that fits your injured finger and use it as a tourniquet to control blood loss, relieving pressure from time to time.

Steri-Strip.png

[rocklaurence]

If your concerned about that area, I'd box that section. There's plenty of room to work in that area.

[candymancan]

I am a bit concerned about it yea. Not like freak out concerned but i am without it being fish plated. But i had my friend a welder of 25 years who did pipe welding look at it. And he said besides me going down on the welds versus going up. It should be fine and not need anything else.

But the boxing in idea i like. Thanks ill take that into consideration.