LOST JEEPS :: View topic - Ironrock Rear Upper Control Arm Install on Liberty KJ

Nice work.
You got any drawings and measurements for the bracket?
I can take measurements and do a drawing! Will try and do that today!

Any plans to fab up a few more?

Making the adaptor was easy, 2" X 3" 1/4" thick angle iron about 7 inches long. 1" X 1" 1/4" thick angle iron about 6 inches long to connect to third lower bolt hole.
All bolts holes are 9/16". Will get exact length measurements and post!

Maybe I could come up to GA and give you a hand :wink:

More than welcome! Can be welded up and installed in about an hour or little more provided you have the WJ mount that comes with the Ironrock control arm.
The WJ mount that comes with the Ironrock arm is welded to the top of the angle iron adaptor and set as far back as possible against the boss where the speed sensor bolts into the rear differential housing.

How hard is it to adjust pinion angle?
To adjust, you simply screw the center bolt section in or out. (see picture! you lock it in place with the very large nut)
I measured and recorded driveshaft angle before taking old boomerang off and I was right at 19 degrees. I tried to get new arm to set in exact mounting locations, but new arm is just a tad longer than the boomerang. I even cut about 1 inch off the end of the new arms center adjustment bolt so I could screw it in as far as threads allowed. I was able to get within 1 degree of original angle after bolting everything together. So, I lost 1 degree and driveshaft angle was 18 degrees! But looking at angle of driveshaft in relation to pinion angle, they are more in line now than they were. Road test revealed no vibrations at any speed; actually was much smoother and no more ka-klunk sounds when shifting up or down between gears with this new control arm which is one of the main reasons I installed it.
If you installed some slightly longer lower control arms, you could set angle at any degree you desire. :wink:

Awesome!
Ok, one more question.
When welding the Ironrock bracket onto your homemade bracket, how did you ensure that the axle was squared up and the Ironrock bracket was centered over the axle?
Or did you just wing it? :wink:

How much did this end up costing? I know JBA has their bolt on 4 link now to replace the boomerang but it's like $595.
Sent from my iPhone using Tapatalk

I am intrigued by this upgrade, WWDiesel. I would like to be brought up to speed on the advantages of this upgrade.
Is there a problem with the O.E. arm?
YES!!!! Poor quality mass produced piece of stamped metal with very soft dampers on the ends where it mounts to the body that wears out prematurely allowing excess movement (noise) during normal torque transitions between gear shifts of the transmissions!
Replacement part (boomerang) are no better in quality or worse and cost almost 2/3 or better as much as the Ironrock unit!
The Iron Rock arm looks really stout, and I like the fact that it is adjustable. Is the purpose of the adjustability to help align things when a lift kit is installed?
It is super stout! Replacing the factory boomerang with the Ironrock trilink will be the last time you ever replace this part! The bushings are much more robust and the single swivel ball joint has a grease fitting so it is greaseable! Sort of like the JBA upper control arms!
Adjustability is just an added plus if needed if you add a lot of lift or longer lower control arms to your KJ!

So I was looking at my boomerang and it is pretty rusted. Bushings seem good for now but this mod is nice and would be pretty much all upgraded rear for me which I like. You think it would work for a 6 inch lift? The jeepinbyal has a big riser now off the pumkin and I notice this is right on top..

ryanchris wrote:

I see no reason why it would not work with any lift! It is super adjustable so you could set driveshaft angle at any angle desired! :wink:

For my 2.5" lift, I actually had to cut a little bit off the end of the threaded piece so I could screw it all the way to the bottom of the threads trying to keep the same driveshaft angle as the OEM boomerang.
It has been installed now since October with zero problems! And the best part, the klunk is gone when shifting gears up or down at low speeds! :BANANA:

IIRC, the WJ rear ball joint is centered with the axle tubes. More than likely, when mounted to the WJ axle, the heim joint is centered with the axle tubes. Did you consider designing you bracket so the heim joint is at the centerline of the axle? I think moving the bracket rearward would provide more adjustment.

Author:	WWDiesel [ Wed Oct 18, 2017 3:11 pm ]
Post subject:	Ironrock Rear Upper Control Arm Install on Liberty KJ
Replaced the rear "Boomerang" upper control arm with a Ironrock unit. Replaced the "Open" differential with a new Trac-loc unit at the same time. Had to engineer, fab, and weld an adaptor to the WJ mount, super strong and works perfect! All 1/4 & 3/8 metal double and / or triple welded for strength! Incorporated all three bolts and added an additional brace off rear for additional strength which was probably not really needed! Mount turned out to be a lot easier to build than I had originally thought! This is one super strong, well built unit!!! Pictures of install:

Author:	KJ/toy [ Wed Oct 18, 2017 9:33 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
Looking good.... Let us know how it turns out....

Author:	flash7210 [ Thu Oct 19, 2017 8:57 am ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
Nice work. You got any drawings and measurements for the bracket? Any plans to fab up a few more? Maybe I could come up to GA and give you a hand How hard is it to adjust pinion angle?

Author:	WWDiesel [ Thu Oct 19, 2017 10:02 am ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
flash7210 wrote: Nice work. You got any drawings and measurements for the bracket? I can take measurements and do a drawing! Will try and do that today! Any plans to fab up a few more? Making the adaptor was easy, 2" X 3" 1/4" thick angle iron about 7 inches long. 1" X 1" 1/4" thick angle iron about 6 inches long to connect to third lower bolt hole. All bolts holes are 9/16". Will get exact length measurements and post! Maybe I could come up to GA and give you a hand More than welcome! Can be welded up and installed in about an hour or little more provided you have the WJ mount that comes with the Ironrock control arm. The WJ mount that comes with the Ironrock arm is welded to the top of the angle iron adaptor and set as far back as possible against the boss where the speed sensor bolts into the rear differential housing. How hard is it to adjust pinion angle? To adjust, you simply screw the center bolt section in or out. (see picture! you lock it in place with the very large nut) I measured and recorded driveshaft angle before taking old boomerang off and I was right at 19 degrees. I tried to get new arm to set in exact mounting locations, but new arm is just a tad longer than the boomerang. I even cut about 1 inch off the end of the new arms center adjustment bolt so I could screw it in as far as threads allowed. I was able to get within 1 degree of original angle after bolting everything together. So, I lost 1 degree and driveshaft angle was 18 degrees! But looking at angle of driveshaft in relation to pinion angle, they are more in line now than they were. Road test revealed no vibrations at any speed; actually was much smoother and no more ka-klunk sounds when shifting up or down between gears with this new control arm which is one of the main reasons I installed it. If you installed some slightly longer lower control arms, you could set angle at any degree you desire. https://www.ironrockoffroad.com/product ... short.html

Author:	flash7210 [ Thu Oct 19, 2017 12:35 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
Awesome! Ok, one more question. When welding the Ironrock bracket onto your homemade bracket, how did you ensure that the axle was squared up and the Ironrock bracket was centered over the axle? Or did you just wing it?

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Author:	WWDiesel [ Thu Oct 19, 2017 1:16 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
flash7210 wrote: Awesome! Ok, one more question. When welding the Ironrock bracket onto your homemade bracket, how did you ensure that the axle was squared up and the Ironrock bracket was centered over the axle? Or did you just wing it? Held rear axle in place and current angle with supports before removing OEM boomerang, see picture. Bolted the Ironrock arm in place with the adaptor bolted in place with the WJ mount setting on top of adaptor and then marked both front and side locations on the bottom of the WJ mount with a sharp steel scribe. Then removed the adaptor and WJ mount, lined them up in vise and welded the heck out of them. Double pass welds on inside and outside on both sides and front and then a triple pass weld on bottom rear for super strength... I then welded in side pieces (gussets) on each end of angle iron to add additional rigidity.... you can see them in pictures on original post!

Author:	mass-hole [ Fri Oct 20, 2017 3:24 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
How much did this end up costing? I know JBA has their bolt on 4 link now to replace the boomerang but it's like $595. Sent from my iPhone using Tapatalk

Author:	WWDiesel [ Sat Oct 21, 2017 2:33 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
mass-hole wrote: How much did this end up costing? I know JBA has their bolt on 4 link now to replace the boomerang but it's like $595. Sent from my iPhone using Tapatalk $325.00 including shipping for Ironrock control arm with WJ mount included.! Two pieces of 1/4" angle iron, I had on hand. Time and welding, I did myself. I priced the WhitbyKJ designed custom WJ mount before deciding to engineer and build my own. Price from Iron Forge Customs whom I contacted and who now builds them was $180.00 plus a two week lead time. I did not want to wait that long and felt price a bit high for something that I could build myself. The adaptor I designed and welded to the WJ mount was much less cost wise!

Author:	TURBO-DIESEL-FREAK [ Sun Oct 29, 2017 6:29 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
I am intrigued by this upgrade, WWDiesel. I would like to be brought up to speed on the advantages of this upgrade. Is there a problem with the O.E. arm? The Iron Rock arm looks really stout, and I like the fact that it is adjustable. Is the purpose of the adjustability to help align things when a lift kit is installed?

Author:	WWDiesel [ Sun Oct 29, 2017 10:00 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
TURBO-DIESEL-FREAK wrote: I am intrigued by this upgrade, WWDiesel. I would like to be brought up to speed on the advantages of this upgrade. Is there a problem with the O.E. arm? YES!!!! Poor quality mass produced piece of stamped metal with very soft dampers on the ends where it mounts to the body that wears out prematurely allowing excess movement (noise) during normal torque transitions between gear shifts of the transmissions! Replacement part (boomerang) are no better in quality or worse and cost almost 2/3 or better as much as the Ironrock unit! The Iron Rock arm looks really stout, and I like the fact that it is adjustable. Is the purpose of the adjustability to help align things when a lift kit is installed? It is super stout! Replacing the factory boomerang with the Ironrock trilink will be the last time you ever replace this part! The bushings are much more robust and the single swivel ball joint has a grease fitting so it is greaseable! Sort of like the JBA upper control arms! Adjustability is just an added plus if needed if you add a lot of lift or longer lower control arms to your KJ! Jeff you like to build and market speciality things for the Jeep Liberty, maybe you should consider adding this mount adaptor to your products? It is a simple adaptor that allows the WJ mount along with the Ironrock control arm to bolt up to the OEM Jeep Liberty differential housing!

Author:	ryanchris [ Wed Jan 03, 2018 8:59 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
So I was looking at my boomerang and it is pretty rusted. Bushings seem good for now but this mod is nice and would be pretty much all upgraded rear for me which I like. You think it would work for a 6 inch lift? The jeepinbyal has a big riser now off the pumkin and I notice this is right on top..

Author:	WWDiesel [ Thu Jan 04, 2018 12:50 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
ryanchris wrote: So I was looking at my boomerang and it is pretty rusted. Bushings seem good for now but this mod is nice and would be pretty much all upgraded rear for me which I like. You think it would work for a 6 inch lift? The jeepinbyal has a big riser now off the pumkin and I notice this is right on top.. I see no reason why it would not work with any lift! It is super adjustable so you could set driveshaft angle at any angle desired! For my 2.5" lift, I actually had to cut a little bit off the end of the threaded piece so I could screw it all the way to the bottom of the threads trying to keep the same driveshaft angle as the OEM boomerang. It has been installed now since October with zero problems! And the best part, the klunk is gone when shifting gears up or down at low speeds!

Author:	ryanchris [ Thu Jan 04, 2018 2:23 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
Sweet. Might be a spring project for me. Now i just need to get a welder and mess up a lot of practice pieces before i try to tackle that bracket.

Author:	95Z28A4 [ Sun May 06, 2018 11:10 pm ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
WWDiesel wrote: ryanchris wrote: So I was looking at my boomerang and it is pretty rusted. Bushings seem good for now but this mod is nice and would be pretty much all upgraded rear for me which I like. You think it would work for a 6 inch lift? The jeepinbyal has a big riser now off the pumkin and I notice this is right on top.. I see no reason why it would not work with any lift! It is super adjustable so you could set driveshaft angle at any angle desired! For my 2.5" lift, I actually had to cut a little bit off the end of the threaded piece so I could screw it all the way to the bottom of the threads trying to keep the same driveshaft angle as the OEM boomerang. It has been installed now since October with zero problems! And the best part, the klunk is gone when shifting gears up or down at low speeds! IIRC, the WJ rear ball joint is centered with the axle tubes. More than likely, when mounted to the WJ axle, the heim joint is centered with the axle tubes. Did you consider designing you bracket so the heim joint is at the centerline of the axle? I think moving the bracket rearward would provide more adjustment.

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Author:	WWDiesel [ Mon May 07, 2018 9:12 am ]
Post subject:	Re: Ironrock Rear Upper Control Arm Install on Liberty KJ
95Z28A4 wrote: IIRC, the WJ rear ball joint is centered with the axle tubes. More than likely, when mounted to the WJ axle, the heim joint is centered with the axle tubes. Did you consider designing you bracket so the heim joint is at the centerline of the axle? I think moving the bracket rearward would provide more adjustment. The centerline of the heim joint is in the exact same side to side location as the OEM KJ boomerang ball joint along with the same angles for the triangulated arms. Only difference is the IronRock arm heim joint is adjustable in and out or front to rear which allows some pinion angle adjustment. When designing the bracket, I did not locate the centerline of the entire differential axle assembly as I was more concerned as to making sure the IronRock arm's angles and mounting locations were in the same locations as the OEM boomerang. See picture below of IronRock Arm bolted to the top of an OEM boomerang: As to moving the bracket rearward, I have located as far to the rear as possible due to the boss that sticks up on the 05 where the rear speed sensor is located. If the 06 does not have the speed sensor boss on the differential housing, it may be possible for a little more rearward location on them, but I suspect it would be very small...