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  #1  
Old October 14th, 2020, 18:47
maxbraketorque maxbraketorque is offline
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Rear unibody bracing?

It appears that I can get a good amount of bracing and stiffening at the front of the unibody using a combo of a track bar brace and steering box + sector shaft bracing (probably purchasing the Ironman4x4Fab stuff), but I'm wondering if there are any bolt on solutions to tying together the unibody at the rear. From what I've been able to find, it appears that the two primary options are an aftermarket bumper with additional attachment points to the unibody rails or a trailer hitch kit. Some people have suggested that the JCR gas tank skid plate may also help, but I haven't seen any confirmation of this. Are those the options for the rear, or is there anything else?
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  #2  
Old October 14th, 2020, 18:58
RCP Phx RCP Phx is online now
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Re: Rear unibody bracing?

The most strength you can get is in a good bumper.
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  #3  
Old October 14th, 2020, 19:27
Black1990jeep Black1990jeep is offline
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Re: Rear unibody bracing?

a sturdy bumper that is mounted to a reinforced frame is best. The reinforcement can be a 1/8 inch wall thickness square tube, I think 2 x 3 or 4 inches. then weld or bolt it to a sturdy bumper and slip them in the frame, then bolt to the frame.

Thats what I done did.

The stock bumper mounts are worthless, and wont help much, they are weak sheet metal, hence the need to insert square tube into the frame and from the tubing, which is bolted to the bottom of the frame, the tubing is welded to a flange (3/8 in. thick) that is threaddd to accept a strong bumper using stock bolt pattern.

passenger side tube was near 22 inches .long, but driverside tube could only be maybe 8 inches long do to the gas tank filler pipe that passes thru the driverside frame. I extended this by using a short 1x2 channel (or maybe it was 3/4 x 2 inch) welded to the eight inch
long square tube. it was short enough to pass under the filler pipe. that way I got a full 22 inch or so i to the frame on both sides. I also have an aftermarket steel gas tank skid box that may offer some stiffening.

I got a set of center frame stiffeners that I be welding into the xj soon.
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  #4  
Old October 15th, 2020, 04:27
75SV1 75SV1 is offline
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Re: Rear unibody bracing?

I'm wondering if the JKS rear shock mount would help stiffen up the rear. Rusty's might make something similar.
https://jksmfg.com/i-9052792-cheroke...ock-mount.html

There is also some welding rear bracing. :
http://www.t-mfab.com/store-3/xj-unibody-stiffiners/


I have their inner front and rear. I might do the rear plate latter, or on another build. Also, the JKS rear shock mount brace on another build. Present build is way over built for a 2" lift.

Also, a trailer hitch drawbar might act as a stiffener.

Edit Again: I will also be adding an Iron Rock bumper.

Last edited by 75SV1; October 15th, 2020 at 07:44.
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  #5  
Old October 15th, 2020, 06:10
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Re: Rear unibody bracing?

Best thing for most is a hitch or good bumper......and if you want to do more, then you can do the frame inserts and they even sell stiffeners for the rear frame as well.

I plan on doing inserts and a good bumper & hitch on mine......
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  #6  
Old October 15th, 2020, 07:46
SlowXj SlowXj is offline
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Rear unibody bracing?

I think a bitch does more than most off-road bumpers due to a bunch of bumpers using the factory bumper horns... The tube tie ins with a good bumper would be the best imo...
My personal xj has is .25" tube insert bumper tire ins, 3/16 frame stiffeners, and an aj off-road bumper that has 3/16 angle welded to the bumper that extends down the bottom of the unirails similar to a hitch.... Overkill, but a stout setup.

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  #7  
Old October 15th, 2020, 07:47
SlowXj SlowXj is offline
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Rear unibody bracing?

Wow I meant hitch.... Dang autocorrect

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Old October 15th, 2020, 08:56
maxbraketorque maxbraketorque is offline
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Re: Rear unibody bracing?

Quote:
Originally Posted by TRCM View Post
Best thing for most is a hitch or good bumper......and if you want to do more, then you can do the frame inserts and they even sell stiffeners for the rear frame as well.

I plan on doing inserts and a good bumper & hitch on mine......
Anyone have suggestions on hitches and bumpers? All the bumpers I reviewed didn't seem to show how it attaches to the vehicle. The AJ Offroad bumper is the first exception to this that I've seen.
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Old October 15th, 2020, 09:06
SlowXj SlowXj is offline
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Rear unibody bracing?

https://www.ebay.com/itm/Jeep-Cherok...-/124334706683

This is my preference on tie ins regardless of bumper....

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  #10  
Old October 15th, 2020, 09:07
75SV1 75SV1 is offline
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Re: Rear unibody bracing?

Quote:
Originally Posted by maxbraketorque View Post
Anyone have suggestions on hitches and bumpers? All the bumpers I reviewed didn't seem to show how it attaches to the vehicle. The AJ Offroad bumper is the first exception to this that I've seen.
The IRO, has 'brackets' that reach back into the rails. I do have one. I think Dirt Bound does too. From some post though, they have 3 bolts instead of 4. There are sellers for brackets that go back into the rails.

https://www.ebay.com/itm/Fits-1986-2...AOSwA49c3J9 i

Last edited by 75SV1; October 15th, 2020 at 09:12.
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  #11  
Old October 15th, 2020, 10:19
maxbraketorque maxbraketorque is offline
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Re: Rear unibody bracing?

Quote:
Originally Posted by 75SV1 View Post
The IRO, has 'brackets' that reach back into the rails. I do have one. I think Dirt Bound does too. From some post though, they have 3 bolts instead of 4. There are sellers for brackets that go back into the rails.

https://www.ebay.com/itm/Fits-1986-2...AOSwA49c3J9 i
This one looks very nice. So, the 4-bolt flange sits flush against the factory sheet metal and uses the factory nuts embedded in the factory sheet metal to attach the bumper to the vehicle? No problem to use the factory bumper with this?

My general impression is that this stiffener combined with the JCR gas tank skid would be a great combo to stiffen up the rear. The vertical sheet metal in the skid should provide an excellent amount of torsional stiffness.
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Old October 15th, 2020, 11:06
75SV1 75SV1 is offline
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Re: Rear unibody bracing?

Quote:
Originally Posted by maxbraketorque View Post
This one looks very nice. So, the 4-bolt flange sits flush against the factory sheet metal and uses the factory nuts embedded in the factory sheet metal to attach the bumper to the vehicle? No problem to use the factory bumper with this?

My general impression is that this stiffener combined with the JCR gas tank skid would be a great combo to stiffen up the rear. The vertical sheet metal in the skid should provide an excellent amount of torsional stiffness.
I think it replaces the factory 'nut strip'. I think you have to cut out the square holes in the frame, that the factory nutstrip slides into.

Edit: Iron Rock Offroad bumper :
https://www.ironrockoffroad.com/prod...per-97-01.html

Last edited by 75SV1; October 15th, 2020 at 12:23.
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  #13  
Old October 15th, 2020, 11:36
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Re: Rear unibody bracing?

Quote:
Originally Posted by maxbraketorque View Post
Anyone have suggestions on hitches and bumpers? All the bumpers I reviewed didn't seem to show how it attaches to the vehicle. The AJ Offroad bumper is the first exception to this that I've seen.
Usually, you have to look for the instructions on the site and you can see from there.

Some ideas on how to strengthen things up:

http://uphillmfg.com/product/jeep-xj...e-in-brackets/

https://www.t-mfab.com/store-3/jeep-...per-stiffiner/
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  #14  
Old October 16th, 2020, 13:00
ridesdirt ridesdirt is offline
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Re: Rear unibody bracing?

another way to stiffen the unibody is to install a cage.

these are bolt in:
https://www.rockhard4x4.com/category_s/350.htm

they are pricey, I had one in a TJ Rubicon I used to own, high quality item for sure...
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  #15  
Old October 16th, 2020, 13:50
RCP Phx RCP Phx is online now
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Re: Rear unibody bracing?

Build something, this is still the rough version of my Cheromanche bumper but you will not flex the frame with it. Unbelievably rigged with the supports trying into all the existing mounts.
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