Rear Upper Control Arm (Boomerang)

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Danihound

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Hello.

I have a 3.7 Automatic KJ, and i wanted to know if its normal to change the Rear Upper Control Arm (Boomerang) every 2 years? this is going to be the 2nd time Im changing cause the ball joint dies, is there any permanent solution?
 

u2slow

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If you are lifted, you are most likely over-angling the joint and bushings.

Mine have lasted well over 2 years.... More like 5-7. Rebushed the original, swapped to another used one later. Have a new spare on my shelf. Zero failures on that balljoint.

JBA makes (or used to make) a tri-link extension. IRO makes a tubular upper with different joints. Both these are for lifted rigs.
 

Danihound

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If you are lifted, you are most likely over-angling the joint and bushings.

Mine have lasted well over 2 years.... More like 5-7. Rebushed the original, swapped to another used one later. Have a new spare on my shelf. Zero failures on that balljoint.

JBA makes (or used to make) a tri-link extension. IRO makes a tubular upper with different joints. Both these are for lifted rigs.

oh thanks, mine is stock.
 

duderz7

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I have replaced the ball joint and bushings in the stock before and it performed well and has lasted until I put the IRO on. I can tell you the IRO is substantially better and well worth the investment if you plan to keep your jeep.
 

Danihound

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I have replaced the ball joint and bushings in the stock before and it performed well and has lasted until I put the IRO on. I can tell you the IRO is substantially better and well worth the investment if you plan to keep your jeep.
Thanks, yes I plan to keep this Jeep, it was my first Jeep so i kinda want to keep it forever haha ;)
 

duderz7

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I'm running the flex joints you definitely hear and feel more vibrations and road noises, but it's not much and you know what it is so it's not concerning. They're tight so don't expect to pump grease in after assembly. Put lots of grease on the joints during assembly.
 

CheddarGau

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I'm running the flex joints you definitely hear and feel more vibrations and road noises, but it's not much and you know what it is so it's not concerning. They're tight so don't expect to pump grease in after assembly. Put lots of grease on the joints during assembly.
Hmm that's a tough call. Ride pretty noisy as it is. Don't want to have to crank my radio more..... but strength and longevity..... tough choice.
 

WWDiesel

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seafish

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IronRock super heavy duty rear control arms are a permanent solution, never have to replace the boomerang again or the two lower control arms.

I see that they also offer it with a rubber bushing as an option…

Any idea if it will work with a stock height KJ ?
 

u2slow

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I don't know what the big deal is changing a $100 boomerang every 5-7 years.

I don't recommend renewing the bushings or balljoint. It costs almost as much, and odds are you stretch the holes on removal, if it's not already rusted so far it crumbles.

The dealer changed our lower control arms as part of a recall. They have been fine.
 

duderz7

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Hmm that's a tough call. Ride pretty noisy as it is. Don't want to have to crank my radio more..... but strength and longevity..... tough choice.
It's pretty minimal, there's not much those rubber bushings can soak up.
Any idea if it will work with a stock height KJ ?
They're designed to be running at a lifted height. The bushing mounts are at an angle for lift. I'd imagine it would would as they're designed to move through that point in the suspension travel. You might be putting extra stress on bushings.
 

u2slow

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Any idea if it will work with a stock height KJ ?
You would want to check if there's room for it at stock height. Seems like the joint on top of the diff stands taller.
 

WWDiesel

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I see that they also offer it with a rubber bushing as an option…

Any idea if it will work with a stock height KJ ?
Yes, it will work perfectly with stock height vehicle. I have installed several of them on stock height Jeep Libertys. They are a very good and heavy duty product and will last the lifetime of a vehicle due to their super heavy duty construction. And, the HEIM joint is rebuildable and the bushings are replaceable if either of them go bad. IronRock sells just the replacement parts if ever needed. So far, I have never had to replace or rebuild any. :)
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MikeH

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With an ‘04 and ‘05 Liberty as daily drivers my experience is these replacement rear control arms do go out too soon. 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.
 
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