Broke my rear upper control arm

[Robin Down]

Last weekend I attended the Cal4Wheel event 'Winter Fun Festival 2018" held in Grass Valley, Calif. Although there was not much show due to the warm weather here in California, there were over 400 attendees and several groups that headed out into the local forests to run trails and look for some snow to play in.

So, I was in a group that had only been on the road for about 45mins, when we stopped to air down before the more challenging part. I noticed a strong smell of burning rubber when I stood outside my rig, and when I looked underneath I found a large groove had been worn into the inner sidewall of my 35" BFG tire, which caused the smell. Upon further inspection, I discovered that the entire rear upper control arm and track bar mount bracket had separated itself from the axle housing! This was causing the axle to shift sideways under the Jeep whenever I made a turn, and the tire rubbed against the upper spring cup causing a deep gouge in the sidewall.

So, since i only had a short way to go to get back to the start, and no on-board welder to make a better fix, I used some Home Depot ratchet straps to cinch it down and 2 more straps to center the axle left and right. I made it back to my hotel no problem and loaded the Jeep on my trailer for the ride home to Boulder Creek.

Here's a couple pictures of the temporary fix - I strapped around the trackbar and the axle to hold it vertically, then used the other 2 straps to hold it diagonally to the rear bumper tiedowns.

I've ordered new beefy brackets from RuffStuff 4x4, and am planning to fix it this weekend.

the new bracket:
https://www.ruffstuffspecialties.com/catalog/R1988-05-06.html

 

[Chris]

Damn, how do you think it snapped? Did you hear it snap?

Did it occur when you were bouncing off a large rock or something? I'm just trying to figure out if it happened due to something you obviously did, or if it failed without you even realizing it.

 

[Jerry Bransford]

What control arms are you running and are there good quality flex joints at both ends or a mixture of a flex joint and bushing? That exact problem is most commonly caused by a poor control arm design that doesn't allow enough flex/articulation range to avoid over stressing the mounting bracket. That exact problem happened to me 16-17 years ago when I was cluelessly running Tera's first generation control arms with bushings at both ends that didn't flex worth a crap.

 

[Robin Down]

Damn, how do you think it snapped? Did you hear it snap?

Did it occur when you were bouncing off a large rock or something? I'm just trying to figure out if it happened due to something you obviously did, or if it failed without you even realizing it.

I was just driving on a flat dirt road when it snapped, but most likely I damaged it back in September when I did a week of wheeling up near Shaver Lake. We ran several trails including Swamp Lake, and it was really tough, so probably cracked it then and its been working it's way loose since. I am just glad it did not break on my way to work - I drive a fairly twisty mountain road to/from work each day and it would have been very dangerous.

 

[Robin Down]

What control arms are you running and are there good quality flex joints at both ends or a mixture of a flex joint and bushing? That exact problem is most commonly caused by a poor control arm design that doesn't allow enough flex/articulation range to avoid over stressing the mounting bracket. That exact problem happened to me 16-17 years ago when I was cluelessly running Tera's first generation control arms with bushings at both ends that didn't flex worth a crap.

I am running RC long-arm lift with 4" springs, upgraded the F&R trackbars with JKS upgrades. These arms do have busing at one end and flex joints on the axle side. I will see how much flex I am getting from the arms, and these new brackets are super stout so if anything breaks it will probably be the axle housing! ;-)

 

[Ahoragi]

There was a post about this very same thing happening to someone else. Blaine stated that the raised trackbar mount stresses that bracket and causes it to fail.

https://wranglertjforum.com/threads/cracked-frame-suspension.7703/#post-110347

The bracket didn't fail from upper control arm stress, it failed from the track bar trying to do it's job. The picture isn't clear enough but there is a non stock nut, bolt, and washer showing which can point to a raised mount for the trackbar which is what typically takes out the stock mount.

 

[Robin Down]

There was a post about this very same thing happening to someone else. Blaine stated that the raised trackbar mount stresses that bracket and causes it to fail.

https://wranglertjforum.com/threads/cracked-frame-suspension.7703/#post-110347

Yes, I have the raised trackbar mount on my rear upper control arm - i actually welded the bracket to the mount, because I thought it would flex it's way loose. One more thing to periodically check, see if cracks develop in any of the brackets with lateral loads...

 

[Jerry Bransford]

Beefed up control arm mounts is not the answer, that'd be exactly what you don't want to do. Better control arm designs work fine with the stock control arm mounts. I've been running Currie Johnny Joint control arms for 10+ years with the factory mounts on the toughest and most uneven trails imaginable. Never any bracket damage. When I did have torn brackets I was running Tera's crappy 1st generation arms which had next to no flex or articulation available which stressed several mounts to the point of failure.

Once the control arm's flex joint design has enough available angular movement and movement/articulation there will be insufficient force available against the mount to damage it.

 

[Chris]

What Jerry says makes perfect sense. The beefed up control arm mounts won't solve a single thing if the control arms themselves aren't designed to do the sort of stuff you're doing.

 

[mrblaine]

Beefed up control arm mounts is not the answer, that'd be exactly what you don't want to do. Better control arm designs work fine with the stock control arm mounts. I've been running Currie Johnny Joint control arms for 10+ years with the factory mounts on the toughest and most uneven trails imaginable. Never any bracket damage. When I did have torn brackets I was running Tera's crappy 1st generation arms which had next to no flex or articulation available which stressed several mounts to the point of failure.

Once the control arm's flex joint design has enough available angular movement and movement/articulation there will be insufficient force available against the mount to damage it.

His didn't fail from the control arm stresses. It failed because the extended mount for the trackbar added more leverage against the base of the mount and the continual back and for motion of the chassis over the axle let the trackbar eventually take out the mount. Very common with mounts that are not braced to the pumpkin or welded to the tube like Currie does. We've fixed several just by welding the mount back together nicely and then installing the weld in Currie mount. If I'm not mistaken Jerry, didn't you use to run the Tri-County Gear brace on your red Jeep's Dana 44?

 

[Jerry Bransford]

Jerry, didn't you use to run the Tri-County Gear brace on your red Jeep's Dana 44?

I did and I still do. I welded my Currie track bar mount in but I still run that brace out of habit I guess.

 

[JeepNWilly]

Is this the brace?

 

[4x4king]

How did your story end?
I just had the same thing happen to me, I’m not sure which way to go yet, I just rebuilt the axle so I’m thinking finding the right bracket and welding it on, with a new adjustable trac bar?
any suggestions?

 

[Bigfoot15]

Same thing just happened to me on my 2016. Do you recommend a re-weld?