Rear Upper Control Arm (Boomerang)

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seafish

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It matters which one you buy. I’ve done two Mevotechs that were junk. The rubber bushings cracked within two years. One from Napa has lasted many years.

Even though it’s possible and likely that they both came off the exact same assembly line :oops:
 
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I went to Iron Rock’s site and their filter does not have Liberty (KJ) as an option. I just put in a MOOG Boomerang on mine and was curious about price on the IRO one. They must have dropped the KJ line, I an assuming due to lack of sales. Bummer cuz that thing looks bullet proof for sure!!
 

duderz7

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That's too bad. The arm is the same as a a wj if I'm remembering correctly. There was a member on here making the necessary bracket, wwdeisel, not sure. Sorry, I'm not being super helpful.
 
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That's too bad. The arm is the same as a a wj if I'm remembering correctly. There was a member on here making the necessary bracket, wwdeisel, not sure. Sorry, I'm not being super helpful.
No worries I just replaced the original one at 180K and the MOOG replacement looks much beefier so since I don’t run mine off road hard it should last another 180K! I was just curious cuz that thing is nice!!!
 

JMichael2006

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No worries I just replaced the original one at 180K and the MOOG replacement looks much beefier so since I don’t run mine off road hard it should last another 180K! I was just curious cuz that thing is nice!!!

No worries I just replaced the original one at 180K and the MOOG replacement looks much beefier so since I don’t run mine off road hard it should last another 180K! I was just curious cuz that thing is nice!!!
Iron Rock still makes the upper link for the KJ, here is the link https://www.ironrockoffroad.com/product/kj-adjustable-rear-a-arm.html

It is $450, but we'll worth it.
 

seafish

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Giddyup is starting to experience the random loud clunk and vibration and even shimmy in the rear end at hoghway speds. It has happened twice now in the last few months and is startling. I am thinking that something with rhe cheap UCA I installed is locking up and then releasing.

I am NOT quite sure how to easily check for play in the rubber bushings and center balljoint.

Should I use pry bar and check the bushings and baljointwith the rear end in the air and supported on the axle tube? Or with the susoensuon at full droop.?

Also would like to check the LCAs and shock mounts and springs and need to specifically know the easiest/best way to do that as well.

TIA!!
 

DadOSix

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Check you VIN thru the dealer and see if your LCA recall was ever performed. The newer once are much tougher, but do fail as well.

Fish tail at HW speed, sway to the right or left on acceleration and the opposite side on decel is usually LCA until proven otherwise.

Clunk is the boomerang 90 % of the time.
 

mercdudecbr600

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IMO, replace Lca with the IRO adjustable ones. Not only beefier but useful to set track length when lifted. Had them on for 5 years or so, bushings still solid.
 

seafish

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Check you VIN thru the dealer and see if your LCA recall was ever performed. The newer once are much tougher, but do fail as well.

Fish tail at HW speed, sway to the right or left on acceleration and the opposite side on decel is usually LCA until proven otherwise.

Clunk is the boomerang 90 % of the time.

Yes…LCAs were done under recall about 7 years ago after I noticed the acceleration/deceleration swaying. That was woerd enough. lol.

No sway this time…just a loud and random clunk in back and a shimmy as the rear wheels "realigned" on the highway at speed.

I figure that is the cheap UCA that I installed during Covid, but want to find out or sure before I splurge onthe Iron Rock UCA.

Of course, could also be shock towers.

Would still like to know best prcatices for checking the rear UCA.

TIA
 

mercdudecbr600

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Before you order uca I’d check bolt tightness of lcas. Not sure if there’s a good or easy way to check uca ball joint without removing. But you can check the bushing to see if they are cracked/split. In my experience it’s the bushings that give up first.
 

u2slow

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But you can check the bushing to see if they are cracked/split. In my experience it’s the bushings that give up first.

Yup - highest chance those are torn. Having any lift, which angulates the bushings, speeds up that failure.

The arm itself is stupid-simple. About all it can do is rust away.
 
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seafish

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highest chance those are torn. Having any lift, which angulates the bushings, speeds up that failure.
I will inspect the bushings on the UCA more closely.
NO lift, but lousy roads and cheap parts ARE in the mix.

Once again, any protocol for checking for actual play in the UCA, other then visual inspection??
 

u2slow

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I will inspect the bushings on the UCA more closely.
NO lift, but lousy roads and cheap parts ARE in the mix.

Once again, any protocol for checking for actual play in the UCA, other then visual inspection??
Torn rubber bushing are visible when you get your head right in there. I put moog ones in the first time and they tore just the same (since i had lift with no arm-angle correction).

Try a prybar between the arm and body and see if it shifts around far enough for the two to make contact.
 

derekj

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I will inspect the bushings on the UCA more closely.
NO lift, but lousy roads and cheap parts ARE in the mix.

Once again, any protocol for checking for actual play in the UCA, other then visual inspection??
I have found that with the vehicle on the ground put a breaker bar on a wheel nut and give it a quick stab in the tightening direction - if the ball joint on the upper arm has play you should be able to hear and see it move.
 

Dave_too

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is this turning into a show off your IRO?... Or did I totally miss the social que?
By any chance, is that mounted downside up? :) Structurally, I don't see that it would make a difference. That thing is bulletproof.
 

duderz7

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By any chance, is that mounted downside up? :) Structurally, I don't see that it would make a difference. That thing is bulletproof.
It is not. It's very specific in the directions that you should be able to read the read it from the top. The 2 mounts at the body are angled to sit closer to flat.
 

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