Stupid unibody! Bumpers are for frames!!! (Must see!!)

I've looked all over this site and only found ONE post that has found this problem, but there was zero advise on how to fix it. So I'm just thinking that all of you out there with rear tire carrying bumpers need to catch this before it becomes as bad as this. It's a spot that nobody really even sees. I only found it while loading up for a camping trip a couple weeks ago when my rear tailgate was up. I will be starting the repair tomorrow night @ work and I'll post all of the pictures as I go. Using the resources I have(very little mild steel @ an aerospace plant), I'm going to TIG weld the cracks up using Argon gas back-up, and I'm then going to TIG weld 1/8" CRS plate all around the 4-bolt pattern on each side and plug weld them in the center. Then I'm going to tie the 2 plates together with another 1/8" plate between to spread the load. I'll then bolt my bumper back on and build gusseting braces that will bolt to the trailer hitch to prevent anymore undue stress on the rear bumper mounts. Repair pictures will be coming soon, so stay tuned and check your bumpers!!

Might want to think about tying into those faux "framerails" where the hitch mounts so you can use every bit of strength an xj has... If you haven't already that is.

Tying into the hitch with bolts is in my plan, (read the original post!). Besides welding the shiit out of the cracked areas, it's the only way to prevent further problems. I'm a Sr. welding specialist with 15yrs exp in custom fabrication, so I think this thread should provide anyone with the same problem, a good solid fix to this problem.

There are lots of threads on this.The problem is that you mounted a bumper that didn't tie into the framerails nutserts!

Drill out the ends of the cracks and weld it back up as much as you can. Then punch on the stock nuts used for the bumper bolts that are spot welding back there. Get a piece of 1/8" plate like 5"x8" and jsut plate right over everything in one shot. Predrill the mounting pattern and weld some 1/2" Gr8 nuts on the backside. You'll end up with new mounts that are pretty much stronger then factory now.

Deffiently a good idea/time to think about building some way better bumper mounts the fit inside the framerail. You'll end up with better mounts and you'll already be cutting out half the cracks to begin with. I use 2x4x.250" rect tubing, fits perfect inside.


http://www.naxja.org/forum/showthread.php?t=993533

Damn! I searched the site for a thread, I guess I wasn't typing in the right words. Rcp Phx, your picture was what I was thinking of doing. I didn't mount this bumper, it was on the Jeep when I bought it. It had two half-assed braces that tied into the very end of the framerails, but they obviously didn't work. Thanks for the advice guys!

I cut out the hole in the center of the 4 bolts where the "frame" is and stuck a piece of 2x4 1/4" wall tubing in there and used the hitch bolts and the rear 4 bolts when I built my bumper/carrier. No problems so far and I carry my 36" spare tire back their. I would never trust just the bumper mounting holes I've seen way to many crack just like yours.

I wouldn't try and punch those nuts out like Ross (foxwar71) said, they are pressed into the "ears" on the end of the "frame rail" which only has a couple spot welds holding it to the rear crossmember. When I tried to punch mine out I only succeeded in mangling the ears. Grind em off or leave them there.

Putting a good strong piece of metal down into the inside of the frame rail (open the end up fully and use 2x4 or 2x2 steel box tubing) or a C-channel down the outside like RCP suggested is the way to go.

not to resurrect a dead thread, but the issue isnt only about not having the bumper tied into the hitch mounting points. I had a tire carrier bumper with a receiver hitch that had flat plate that tied into the hitch points. The problem was that it had no strength to resist bending, so it was find for a straight on pull, but once you put some tongue weight on the hitch, it would deflect, and before I realized it I had cracks (but not this bad). When you tie into the rear hitch points, it needs to be like the picture earlier in this thread with angle iron, or like others have said with a 2x4 inside the rail. For super beef, 2x4 in the rale and then angle on the bottom of it.

The ears from the framerail to the rear x-member on mine cracked, so I drilled out the spots and punched out the nuts. We are going to tie them back together with 1/8" angle iron.