XJ/MJ Concerns

[riverfever]

I agree. The XJ club I belong to has some guys that run really difficult trails. Many have cages for protecting themselves but there are some that have no "frame" stiffeners or cage work and they are structurally fine. I know Sven had issues with his but that thing lived a spirited life. I've seen one other rig that was tweaked a bit but it also had seen quite a bit. I think you'll be fine.

 

[Xtreme XJ]

Detail.... so did you go ahead with the XJ/MJ combo ?
My experience with the XJ (a new 96) is I have cracking on I believe 7 out of the 8 pillars.... mostly small, but I still have minor concerns.... I know some day these will become an issue as I continue to wheel.
Mine was a multi-purpose vehicle for 10 years and I've wheeled the piss out of it, I thought it was going to spin in the middle a few times.... but it has held up well.
I also feel I'll be able to locate a decent vehicle in the future to swap parts over if necessary.
I too don't "need" a cage, but if I were to get a new project I might put one towards the top of my list.... rockrails.... chassis stiffeners quite possibly.
The uni-body is probably the only thing I don't like about the XJ... that and it doesn't have a V-8....
You might as stated check out NAXJA and search for pillar cracking or the likes....

Good Luck...
Curt :safari-rig:

 

[detailbarn]

Detail.... so did you go ahead with the XJ/MJ combo ?
My experience with the XJ (a new 96) is I have cracking on I believe 7 out of the 8 pillars.... mostly small, but I still have minor concerns.... I know some day these will become an issue as I continue to wheel.
Mine was a multi-purpose vehicle for 10 years and I've wheeled the piss out of it, I thought it was going to spin in the middle a few times.... but it has held up well.
I also feel I'll be able to locate a decent vehicle in the future to swap parts over if necessary.
I too don't "need" a cage, but if I were to get a new project I might put one towards the top of my list.... rockrails.... chassis stiffeners quite possibly.
The uni-body is probably the only thing I don't like about the XJ... that and it doesn't have a V-8....
You might as stated check out NAXJA and search for pillar cracking or the likes....

Good Luck...
Curt :safari-rig:

yes i am going with the mj/xj build. my wifes xj has no cracks i myself went over it and also had two mechanics look at it and they found nothing. I honestly feel that my concerns where unmerited or atleast overly hyped. All metal can fatigue unibody or not, there was a recent post here about a bed mount cracking on a members tacoma which is body on frame so it doesn't seem to be a big deal. My 2001 Double Cab Tacoma cracked leafs springs left and right so I think as long as I take care of it add frame stiffeners I'll have these vehicles for at least 25 more years.

 

[Offroader5]

My XJ is sitting with 8" and 35's and when I wheel it, I wheel it on some difficult trails. It really only sees rocks ie..rock crawling on 3 & 4+ trails (on the 5 scale)....and I have yet to even twist the unibody to the point of it causing any damage. If this happened, the first thing you'd notice is that the doors don't line up anymore. The doors (when closed) add alot of structure to the "frame".

One thing in lieu of the stiffeners...is to install some good sliders. I have a set of sliders I built that go back to the unibody "frame rail" with 4 legs and then they also bolt the entire length of the lower rocker pinch seam with 10 bolts with a piece of small angle welded across these legs. This, I think, has kept the twisting to a minimum. Think about it...the continuous piece along the pinch seam is tieing the whole length of rocker together with the frame rail and keeps it from twisting. It's an option

Click the thumbs for big versions:



Not only are you stiffening the unibody this way...but you also gain the rocker protection with the slider rail

 

[Alex]

My Cherokee is a 1997 with 170,000 miles and I have had/am having unibody issues. It has been on 33's and wheeled regularly since June of 2001...

The first problem is also the most common- the "frame rail" below the steering box develops a crack and the laminated lower sheetmetal layers start to buckle and seperate.

This seems to be caused by the installation of an aftermarket front bumper for mounting a winch. The Cherokee body in stock form does allow some twisting, the trouble starts when you bolt a highly rigid, heavy front bumper to it. The body still twists, the bumper doesn't. Something has to give. Bolt-on steering box braces excaberate the situation. Use the reinforcing plates that weld or bolt on to the sides of the uniframe.

The next major failure was the leaf spring shackle body mounts.

Fixed like this:

I have been developing cracks where the roof meets the pillars for a while, as well as cracks at the corners of the vents in the door sills. On my last trip I noticed the passanger door no longer contacts the body when closed. On closer inspection, the roof forward of the factory roof rack rails has a downward bow and the floor pan is starting to seperate from the frame rails. Yes, my beloved Cherokee is starting to resemble an old swaybacked horse. I have some T&T frame stiffeners ready to install as a band-aid, unfortunately my fabricator has moved on from his last position.

Keep in mind that my Jeep has lead an unusually tough life. It weighs at least 5000lbs when I leave on a trip and gets wheeled hard. I also put many miles on bad dirt roads, usually at higher speeds than is wise. If I were to start over I would do frame reinforcements first. Here is a good example:

http://www.naxja.org/forum/showthread.php?t=913774

I am probably going to keep on patching my current Cherokee. It is a 2 door, 5-speed, which are very hard to find in the 97-up body style. If a clean one were to appear for sale, that would be another story. This one took 4 months to find so I am not holding my breath.

 

[detailbarn]

wow most of the post here and naxja have told me my concerns where unmerited but now this last post. personally I thank everyone for their input on my concerns. I have at this time deicided to go with the xj and mj, I own them and the really fit my needs well.

Alex I am shocked to see how bad your xj is , personally I will never push either of my trucks that hard. My opinion is that the way you've used your truck is border line abuse not just normal expedition use. Not a bad thing but something to be expected with a trail rig that gets beat. A friend of mine got similar damage on hi 98 TJ and that was full frame.


So my conclusuon is I will add sliders with frame stiffeners and gusset or support any other area I think needs it during my build. I plan on using ARB bumpers for both vehicles and the MJ with have a snow plow too the front will be boxed nicely. If I need to replace these vehicles in the future I will have to go back to toyota and will probally end up doing a 80 series or two.For now the jeeps are the plan and the builds will start soon so look for a new thread cataloging their progress over the next few years.

Thanks again to everyone!

 

[Alex]

Actually I am careful to not abuse my Cherokee. What you are seeing is 6 years cumulative effect of hard off road use. Now my buddy John is another story- this is 2 years of use, he trailers his Jeep everywhere:

 

[Offroader5]

Any rig's frame or body will see those problems with "abuse". I have been doing the more technical trails with my XJ now for more than 3 years and still have not had any major damage. I have a couple small rock kisses in the body from crawlin, but that's about it. I however, am a very technical driver. I take it slow and if the line I'm on isn't working, I try another rather than push my rig and force breakage or damage. It is after all called rock crawling.

I run a large heavy winch bumper with winch on the front, and on it's install, the frame at the steering box was also plated both sides and I ran sleeves through at the bolts. More than likely when the frame gives out at the steering box, it's not due to the twisting force of the unibody, it's due to the frame's overall weakness not being able to handle turning the added torque and weight of the larger tires especially with the added angle of the drag link with the lifts. Also not to mention the added force needed to turn the larger tires when they want to stay stuck in the rocks or want to go the other way.

My 2 pennies....

 

[Alex]

Any rig's frame or body will see those problems with "abuse". I have been doing the more technical trails with my XJ now for more than 3 years and still have not had any major damage.

It took about 3 years for my Cherokee to start cracking...

BTW, I really like your rocker protection!

 

[detailbarn]

alex yeah I'd say your friends jeep i much worse! I guess what each of us think is abuse or just hard use is relative to the area we live and type if wheeling we enjoy.


Offroader5 I agree with pretty much any rig is that see such hard stuff can and probally will see frame damage. I too am a very technical driver and living on the east coast the trucks will mostly see fire roads and well traveled trails with alot of dirt and mud with very little rocks. I'll also only be running 32's on the street and 33's off road on the MJ , the XJ will have 31's all the time. More stain then stock but much less then say 35's.


Thanks again for all the input!

 

[Offroader5]

It took about 3 years for my Cherokee to start cracking...

BTW, I really like your rocker protection!

Thanks....have you seen my Rear Quarter Protection?

 

[Alex]

Wow, beefy! Did you fab up the 1/4 sliders yourself, John? Are you going to put tubes at the roofline too? That area of a Cherokee gets a substantial amount of abuse due to the soft front coil/stiff rear leaf suspension design.

 

[Offroader5]

Wow, beefy! Did you fab up the 1/4 sliders yourself, John? Are you going to put tubes at the roofline too? That area of a Cherokee gets a substantial amount of abuse due to the soft front coil/stiff rear leaf suspension design.

Yeah, I did the slider rails....took some time on those notches for sure

Yeah, I am going to have some protection for the roof. Those quarter sliders are the mid point horizontal for future C & D pillar uprights that will go up to roof sliders that run full length. The truck will end up with a full exo and I am trying to design it so that I can build areas at at time, but not look stupid as I do

 

[Alex]

Sounds good... where do you live? I'm bringing my Jeep over so you can weld in some T&T frame stiffeners and fix this:

 

[Offroader5]

Sounds good... where do you live? I'm bringing my Jeep over so you can weld in some T&T frame stiffeners and fix this:

Now see...shame shame :violent-smiley-031: That should have been one of the first things you did to that axle when you lifted it....that needs a plate on the front side as a gusset.

I am in Apache Junction, AZ...........bring it over...we'll get 'er fixed up :REExeSquatsHL1: