So the word around the forums is the unibody is generally weak, some say prone to issues eventually, etc. I generally agree with this but am curious how frequently it occurs, how bad it turned out, and the abuse put on the structure.

I am curious to hear any stories, first hand or from other sources of any major issues, catastrophes, or nightmares from major unibody abuse, not caused by major rust.

I've searched the forums a bit and only found a few posts relating to small cracks or rust related damage.

Anyone care to share?

 

Subscribed! One of the jobs that I don't even want to start thinkin bout is reinforcing the frame / unibody of the Cherokee.

 

Take a quick look underneath at the frame rails and floor pan.
If its not an extreme rust bucket and you don't plan to do 'Dukes of Hazard' type hill jumps or extreme wheeling...don't worry about it.

 

I have seen pictures on this forum of frame cracks, and the universal opinion of experienced Jeepers is that severe jumping is required to accomplish that kind of damage. So, yes, if you do stupid things, you get bad results.

Yes, rust can do a number on the unibody. That's not news. It's not the end of the world, though. Almost anything sheet metal can be repaired. It's a question of cost vs. benefit. I just replaced the right rear frame rail from just ahead of the wheel well all the way back, to deal with severe rust damage right at the top of the arch. I doubt it would have been cost effective to have a shop do that work, but all it cost me was some welding wire and some odds and ends. Well, and I paid a couple of my teenage sons a hundred each for their labor.

In other words, there's nothing wrong with a unibody. Try to find a passenger car that does NOT use unibody these days. And yes, that includes SUVs.

True trucks are about the only vehicles now that use frames.

 

Besides, it's not unibody anyway.

 

Oh, that's so true. Unibody is terrible. It's just a matter of time before it folds like a taco. We'll be sorry to see you leave our community, but if you have an XJ you should get rid of it as soon as possible. If you don't have one yet, thank your lucky stars you were warned before you made a terrible mistake.

I would suggest a Toyota for you instead.

 

thats what i kept thinking as i read this, "what the hxxx is that STRUCTURE i see under there"!! ive seen the skimpy sheet metal under other cars. not heavy stuff like my 00. bang on it with a hammer and its like an "old" frame.
i bought mine with some engine noise but mostly solid body. id rather fix oil than bad rust. btw my rockers are rock solid!
currently fixing air cond.

image saved!

 

i'll offer my 2 cents.

i've been surprised by the unibody. last year i was stuck in some deep snow on the trail and some guy with a huge diesel toyota buggy goes past me and my buddies without saying anything. so i ask him if he can pull me out. didn't look like he was the type to help someone out, but he accepted anyway and right before pulling a guy riding with him told me "hold on tight, he doesn't **** around" and then proceeded to pull me so hard i bent my drag link 90 degrees before it snapped right at the pitman arm.

for the 30+ seconds he was pulling me, snow flying everything and rolling coal like a ****, i was 100% certain my unibody would fold like a taco like extrashaky said, but the drag link snapped first thankfully.

i assessed the damages a couple days later:

1- passenger side front leaf spring bolt snapped in half, but was still holding the leaf in so i didn't notice right away and drove around like that... pretty sketchy when i found out
2- rear hatch doesn't sit flush with the body, it tilted about a 1/4 inch to the right. still closes fine though, and no leak from the seal.
3- stock steering box was fine (i have unibody ties ins for the front bumper and steel box spacer, which probably helped a lot) and had to get a new drag link. v8 ZJ tie rod held up but got it replaced under warranty because the ball joint was a bit loose.

and that's it. to give you an idea of the force he pulled me, i was sitting straight in the trail, and when he was done trying to pull me out like a jackass i was 90 degree (perpendicular) to the trail...

 

Sounds like you got "helped" by a blithering idiot.

That, or he deliberately decided to wreck your car.

 

X2, remember back in the 80s AMC used to make a big deal about how much stronger the uni-frame on the MJ (Comanche) was than the frames of the competitive Ranger/S10 (which used open C-channel frames at the time), the MJ even had a "one-ton" option (rare/surprising for a compact pickup), and of course the MJ shares its platform with the XJ.


Sure you can crack an XJ uni-frame if you do stupid stuff (like jumping it) or if it is badly rusted (this goes for any vehicle), but there are plenty of people who have cracked the frames on their Blazers/Explores/4-Runners, and even Wranglers doing the same crap. Hell Jeep engineers even ripped the body of an Explorer (the older ranger based ones) off the frame (granted this is more a comment on the strength of the body mounts rather than the frame, but still shows that just because a vehicle is "body on frame" does not automatically make it stronger/better) on the Jeep proving grounds (A course that even the Compass and Patriot completed without damage).

 

I took my doors off and it folded like a taco.

So, I unfolded it, welded in stiffeners, and put the doors back on.

Haven't had any issues since.

 

Not a jeep but you get the idea

 

oh no doubt about that, in retrospect all the signs (big red flags) were there. as soon as the drag link broke he just left with his people. not like i wanted him around anyway, but it shows you the type of character.

glad it happened though, it was a small price to pay to learn a great lesson. and i got to spend the next day with a buddy trying to get out of that trail. the stress of leaving the jeep in the trail for the night + the satisfaction when we were miraculously able to drive the jeep out of there was a great roller coaster of emotions.

 

Lol, A '57 Plymouth shown at the beginning was my very first car only black back in hi school. Talk about learning automotive repair.
Worst rust bucket i ever owned next to the Datsun B210 which bent in half.
But that 'ol Plymouth flat head 6 was indestructable.

 

There are folks who can mess up an anvil with a rubber mallet and bend a digging bar in a sand pile.