72 wagoneer rear frame damage

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ibrokethat2
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72 wagoneer rear frame damage

Post by ibrokethat2 »

so I was able to get the wagoneer up on the lift today to see just how bad the rear frame damage is, well it's as bad as I thought it was. the rear cross member that supports the rear of the body is gone and both frame rails are pretty bent and twisted to about the center of axle arches. so I have three options,1 fab up new rear rail sections, 2 use rear frame sections off of an 80's model frame my buddy has, or 3 use the whole 80's model frame. I haven't had a chance to compare measurements on the two frames I was just wondering how close they are, fabbing body mounts is not a problem and I am not keeping it original so that is not a concern either.
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Stuka
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Re: 72 wagoneer rear frame damage

Post by Stuka »

Which cross member is in the photos? Those welds look absolutely terrible, and that doesn't look like the same material as the stock cross member.

Putting in a new rear cross member should not be that difficult. C channel is available in lots of sizes.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
ibrokethat2
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Re: 72 wagoneer rear frame damage

Post by ibrokethat2 »

I am assuming that the po put that cross member in trying to stiffen up the bent frame rails after the rear cross member was removed. and yes those are some terrible welds.

SJTD
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Re: 72 wagoneer rear frame damage

Post by SJTD »

Looks like he used coat hangers and car batteries.

I'd do the whole frame.

Count the body mounts. Somewhere between '65 and '84 they went to one fewer per side. Idunno about other changes.

Same motor and trans were in the '80 as in yours?
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

Austin4x4
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Re: 72 wagoneer rear frame damage

Post by Austin4x4 »

Maybe I am not understanding this correctly, someone cut out the rear crosmember and welded in another? Why not replace the missing crossmember, and straiten the frame rails?

candymancan
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Re: 72 wagoneer rear frame damage

Post by candymancan »

Is that the rear cross member by the tires.. or the one by the bumper.... The bumper id be less concerned
. but the one above the differential... i dunno man
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

rocklaurence
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Re: 72 wagoneer rear frame damage

Post by rocklaurence »

It looks like a additional member added between the rear spring mounts and the axle. Hmm?

candymancan
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Re: 72 wagoneer rear frame damage

Post by candymancan »

Also how bent amd twisted is this frame can you get a pic ? The wagoneers frame in the rear is bent weirdly to begin with so are you sure its actual damage ?
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

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ibrokethat2
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Re: 72 wagoneer rear frame damage

Post by ibrokethat2 »

So this is what it looked like with the body removed(this is how it was when I bought it), after leveling the frame on jack stands I determined that the frame was only damaged behind the axle arches, the rest of the frame is straight and square so I decided to rebuild the rear section instead of trying to straighten the damaged area the right was not that bad but the left one was worse . had some 2"X4"X1/8" box tubing left over from another project and found that it fit perfectly in side the frame rail.I don't have a completed picture but I will post some when I get them down loaded from my phone.
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rocklaurence
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Re: 72 wagoneer rear frame damage

Post by rocklaurence »

Oh, now I see.. Looks like you got it under control and will be better than OEM

candymancan
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Re: 72 wagoneer rear frame damage

Post by candymancan »

dang lol that was twisted.. glad you got it fixed.


Im not an expert welder but i do weld.. shouldnt frame peices be diamond shaped for welds. long vertical welds i read arent strong from frame rails ?
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
ibrokethat2
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Re: 72 wagoneer rear frame damage

Post by ibrokethat2 »

I will most likely put some diamond gussets over the vertical weld where I mitered the rails.

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ibrokethat2
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Re: 72 wagoneer rear frame damage

Post by ibrokethat2 »

Just about finished, mount the hangers for the swing shackels and put some sleeves through the frame to mount a bumper and trailer hitch in the future. once I get all that done I can actually start swapping the axles out and the engine and transmission/transfer case.
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SJTD
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Re: 72 wagoneer rear frame damage

Post by SJTD »

Looks really good.
Sic friatur crustulum

'84 GW with Nissan SD33T, early Chev NV4500, 300, narrowed Ford reverse 44, narrowed Ford 60, SOA/reversed shackle in fornt, lowered mount/flipped shackle in rear.

rocklaurence
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Re: 72 wagoneer rear frame damage

Post by rocklaurence »

Did you cap the forward ends to prevent debris from filling up the new tubes? If not, cut some drain holes on the bottoms.

Topic author
ibrokethat2
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Re: 72 wagoneer rear frame damage

Post by ibrokethat2 »

yes, I cut the foreward tube ends at a 45 and capped them.
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Stuka
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Re: 72 wagoneer rear frame damage

Post by Stuka »

Nice work. May as well box the rest of the frame in now. You have the front half and the rear 1/4 boxed already.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

candymancan
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Re: 72 wagoneer rear frame damage

Post by candymancan »

Looks really nice... I wish i had a shop to take my body off when i had to weld the frame.. i had to do it laying on the pavement..
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
ibrokethat2
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Re: 72 wagoneer rear frame damage

Post by ibrokethat2 »

I was thinking about boxing the rest of the frame, but was wondering if I really needed to.
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tgreese
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Re: 72 wagoneer rear frame damage

Post by tgreese »

ibrokethat2 wrote:I was thinking about boxing the rest of the frame, but was wondering if I really needed to.
Depends on your preferences. In the CJ world, much of the vehicle's flex comes from the frame twist. Body roll control comes from the stiff springs. Stiffen the frame and soften the springs, and the Jeep now needs some other sort of body roll control.

From what I've seen, the usual failure of these frmes is the rear spring mounts for the front axle pulling off of the frame. This typically leaves a hole in the frame rail, and could be a source of rail failure due to cracking. Good idea to add a reinforcing strap along the frame rail and through the spring mount, IMO ... esp. since you're so well set up to do this.

Now that you have repaired the rear of the frame to be stiffer than the forward part, possible you will have a stress riser where the rear frame meets the front. If it were me, I would ether try to match the flexibility front to rear, or bring the stiffening forward to in front of the rear axle spring hangers, and then taper it off toward the front. This could be done with a fish mouth, at the point where the boxing ends. Could be I'm over-analyzing this ...
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