WJ Grand Cherokee boomerang, KJ boomerang..??

Jeepin'WNC · **Joined:** Mon Nov 15, 2010 1:48 am **Posts:** 191

Does anyone know if the WJ ('99-'04) Grand Cherokee boomerang and the KJ boomerang share the same dimensions? After doing a little research I know that the bracket that attaches the boomerang to the diff is different.... I didn't know that the WJ used a boomerang until yesterday morning while watching Extreme 4x4.... A Rusty's Offroad 4.5" long travel lift kit was being installed on a WJ... The rear upper link in this kit is super beefy, and it's available separate from the rest of the kit!! If this boomerang/ wishbone/ tri-link/ what-ever you prefer to call it, shares the same dimensions as the one on the KJ's... A bracket to attach it to the rear diff of a KJ shouldn't be too hard... Some steel, a little cuttin' of that steel, a couple of bends, a few welds, four holes... Do I see the possibility of no more rear ball joint problems, and pinion angle adjustment, or am I just having a pipe dream??

dakar650 · **Joined:** Tue Oct 25, 2011 8:10 am **Posts:** 1

As I understand it and have read somewhere, the KJ has a modified version of the WJ but I can confirm that the upper bushes are the same part!!

Cheers

RED_KJ_666 · **Posted:** Tue Dec 06, 2011 6:31 pm

The Ironrock Boomerang would work no problems in a lifted appliction, from the Dimensions they sent me and measurements I took.

Jeepin'WNC · **Joined:** Mon Nov 15, 2010 1:48 am **Posts:** 191

That is AWESOME news!!! I've lifted my Renegade 3 inches in the rear; OME 948's and two extra upper isolator's...At first I was running the Frankenlift in front and just the 948's in the rear; that gave me a nose-up, pre-runner look that I didn't really dig. I added two extra iso's in the rear and that gave me the level stance I was after, but after doing that I gained a vibration that is most noticeable in the 40-50 mph range; and a clunk from the rear ball joint. I know that I could probably just replace my rear ball joint and get or make a rear link extension for the boomerang and be OK for quite sometime, but I have a bit of an aversion to anything that claims to be sealed for life...

jamesdart · **Joined:** Wed Oct 06, 2010 4:41 pm **Posts:** 53

i saw that too, and was thinking the exact same thing, the balljoint setup seems to have its limits.

RED_KJ_666 · **Posted:** Wed Dec 07, 2011 9:08 pm

Just build a Triangulated 4-link, it's probably the best way to go if you're moving away from the Factory Tri-Link.

randrson · **Joined:** Thu Aug 25, 2011 7:17 am **Posts:** 2

the axles are different. KJ uses a pressed joint on the arm into a pinch mount bolted to the face of the 9.25. the WJ uses a ball joint bolted to the top of the 35C OR44, and goes through the arm like the front end ball joints. the big similarity is the body bushings and the general demensions.
KJs eat rear UCA ball joints and bushings because they cheaped out the design to ensure ball joints self destruct,especially with the NSG-370 6 speeds. I'm on arm #3, the last one shredded the bushings to total separation- and my is still bone stock. if you need the parts, the best parts still seem to be the OEM for these in off road applications.

But you can most likely design a bolt on adapter that would still place it in the proper location that solves the crap OEM design.

Jeepin'WNC · **Joined:** Mon Nov 15, 2010 1:48 am **Posts:** 191

Red_KJ, I know you are way more experienced in KJ suspensions than I am, and I value the advice of someone more experienced than myself. In simplicity of install and adjustability (pinion angle correction) would a triangulated four link be better for my situation? Literally the night before I saw the episode of Extreme 4x4, I was looking at aftermarket TJ and JK adjustable link arms, looking into the possibility of using them as upper links for a triangulated four link setup for my KJ... I want to get rid of the ball joint design, which could be accomplished by either a four link, or one of the mentioned wish-bone/three link setups. I would like to use the factory location for the forward end of the link(s) which could, again, be accomplished be either. In terms of simplicity wouldn't a wishbone be simpler in both adjusment and in adapting it for use in a KJ? For mounting the rear of the wishbone I was thinking of something very similar to the way JeepinAl mounted his "super flex" rear arms http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=59&t=19626&hilit=super+flex+rear+end I was thinking that I could either bolt or weld the diff bracket that comes with either wishbone to a piece of angle iron, then center the angle iron against my diff and drill holes in the angle iron to mount where the stock boomerang bracket bolted on. Pinion angle adjustment could be accomplished by screwing the rear cartridge joint in or out and I wouldn't have to worry about one link being longer or shorter than the other and possibly "cocking" my diff to one side or the other. I do want you to know that I'm not trying to come across as a smart A-$$, I really do value the knowledge and experience that you've gained in the undertaking of your SFA conversion. I'm really glad that you replied to my post! If there is something that I'm overlooking in my idea, man, school me! That's the reason I asked...Oh Yeah, thanks for bringing the Iron Rock boomerang to my attention. It is $109 less than the one from Rusty's; not quite as beefy as the Rusty's but still overkill for my intended application. If I ever decide that I NEED the Heim joints like the Rusty's link has, the iron rock could always have the bushings cut off, then be tapped for heim joint ends.
Thanks X1000, Casey

jamesdart · **Joined:** Wed Oct 06, 2010 4:41 pm **Posts:** 53

i dont understand why the bushings are verticle instead of horizontal, the bushing takes a beating instead of pivoting on the bolt.

RED_KJ_666 · **Posted:** Thu Dec 08, 2011 8:44 pm

jamesdart wrote:

i dont understand why the bushings are verticle instead of horizontal, the bushing takes a beating instead of pivoting on the bolt.

It's essentially simplicity of mounting, that and for as far as it's going to flex in a IFS KJ application it'll work good.
Jeepin'WNC
I like that setup on Al's looking forward to what ever you come up with as a solution to the problem. I'm just glad you aren't planning on replacing it with a POS factory part. I've said it before and I guess here I go again.... the more people doing something a little different with there Libby's the better, Where would we be if we all built them the same? My guess is the Mall lol...... I still think you're better off to build an upper arm or links than to buy one and modify it to work tho it'll probably take the same amount of work :2cents:

WJ Grand Cherokee boomerang, KJ boomerang..??

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