LJ Coil Spring Quagmire

[Fulton_Hogan]

I've been through entries on this subject here, and I think every other Jeep/offroad/suspension forum I can find online, and I grow ever more confused. So I'm asking anyone who has gone through this drill to chime in. Please.

The Background:
Last year I bought a 2005 TJ Unlimited, or a LJ, whichever you choose. It currently has 104,700 miles on the odometer. Other mechanicals, it has the I-6 and 6-speed manual transmission. Tires are 30x9.5x15. It's a soft-top with full metal doors.
The Jeep had minimal customization, except maybe the tow bar below the rear bumper. This is why I bought it. It was pretty much bone-stock.

The Problem:
This week, while preparing to replace both rear jounce/bump stops because they have dry rotted or gone missing, I see fluid on the bottom of the passenger side rear shock. (All 4 shocks look like originals.) So I think, "Ok, I'll add shocks to the next thing to tackle".
After I got out from under the vehicle I noticed the rear looked slightly saggy, so I measured, and sure enough, the passenger rear is about 1 inch lower than the driver, measured at the welds of the rear and each side quarter panel. The current coil springs all measure close to OEM standards.

I'm fine going to something other than stock/OEM shocks, I was most likely going to Rancho RS5000Xs anyway. However, I know shocks alone don't address ride height. I'll probably need new springs too, but finding near stock-height rear coils has been nothing but trifling. OEM coils is pure futility at this point.

Going aftermarket has started to feel more and more fruitless as well:

Omix-ADA says they offer them for an Unlimited/LJ. But if you look up the "Unlimited/LJ" part number, it's the same part for a TJ.

Moog flat out says, sorry, no dice on a rear Unlimited coil from us.

AC Delco says pretty much the same as Moog. (I half think they sell the same springs just from opposite sides of the factory, because wire sizes, rates, and other data are exactly the same.)

I started looking up Old Man Emu/ARB because people said they make true Unlimited/LJ springs. They appear to offer 3 differently rated springs (light, medium, and heavy) with the heavy ones being recommended for the Unlimited. So I poke around and find people saying in a stock LJ, they got 2.5-3 inches of lift off those OME springs. Too much.

H&R Adventure Raising springs, at 1-1.5 inches, look like the smallest of the additional height, but I find zero technical data on them.

(Sigh.)

Basically, I don't want to get any lift too much over stock height if I can avoid it. I'm ok with stock. I'm not ok with 2.5+ rise. I really don't want to go changing geometries and all that jazz. That feels like a non-starter.

I'm not planning, at any foreseeable time in the future, to add on heavy bumpers, bigger tires, or anything like that. The only custom thing I'm looking to do is get half doors for the summer/warm season. I use this Jeep as a driver and occasionally I get on a sandy trail. I take it slow, ease off the gas approaching stops, the gearing slows me down, and I brake like a grandpa. (That's why I know Mr Blaine's bigger brake kit is not in my future when it comes time for a brake job.)

I do know the Unlimited/LJ has to have more sprung weight in the rear than a TJ, so how can people run TJ springs on an LJ and seemingly be fine? Are they are indeed fine? I don't know.

I do know I don't want to fix one thing (shocks) only to end up having too chuck those because the whatever springs I wind up with are too long.

Any of you who have faced this Unlimited spiral (yes, that was a pun), what has worked? What didn't? What finally proved to be a successful solution for you?


Thanks all!

 

[rasband]

I do know the Unlimited/LJ has to have more sprung weight in the rear than a TJ, so how can people run TJ springs on an LJ and seemingly be fine? Are they are indeed fine? I don't know.

Worst case is you could get the TJ springs and measure where things are and then toss in a spacer in whatever size you need (ish). Depending on what is on your rig it could be fine as is or need something small like a 20mm spacer from OME.

 

[Shwiftypickle]

From what I understand the physical length is the same but the spring rate is different.

 

[never monday]

Theres not a lot of xtra weight in that 15” we have.
Lots of options listed for Rubicon, pick those as they’ll be the stiffest.

 

[Viking Jeeper]

I've read that the actual weight difference of a TJ vs LJ is only about 150 lbs. I really wish I would have weighed my TJ before I sold it for my LJ. You can use the TJ springs and if they dont give you enough, add spacer.

 

[1904-06LJR]

X3 on the TJ springs. Not to mention, you are running a soft top, no plans for rear bumpers, cages, etc. You'll be fine with the TJ springs.

 

[AndyG]

What does the tag say on your rear springs?

 

[Irun]

H&R Adventure Raising springs, at 1-1.5 inches, look like the smallest of the additional height, but I find zero technical data on them.

I've called H&R directly and they won't provide any information about their springs. Other than to tell you they are a progressive spring. That said, having installed two sets, I wouldn't hesitate to use them in your situation. The H&R springs are extremely well made and should work on your stockish LJ with no issues. If you did go that route, you could always have a set of 1" aluminum spacers in reserve. This would allow you to tune the ride height a little, if needed. See post #157 in the link. I'm planning to use them again on a TJ build I'm doing now. There are a few numbers in there for reference. Plus, Tire Rack had the best price on them I could find.

https://wranglertjforum.com/threads/a-lesson-learned—keep-it-light-and-nimble.44924/page-8

 

[Fulton_Hogan]

What does the tag say on your rear springs?

I've previously looked all over those coils and found no remaining tag. I'll look more this weekend when I'm doing the bump stops, but so far, I've found zero.

 

[AndyG]

I've previously looked all over those coils and found no remaining tag. I'll look more this weekend when I'm doing the bump stops, but so far, I've found zero.

There should be a Mopar tag that says 6AA I believe... If we can get Blaine to chime in he can tell you what springs to put on it to do what you want probably.

 

[Fulton_Hogan]

Thank you to all who have replied to this point. All good points. Much appreciated.

Before I even asked this question I had read enough here to think I'd just order Moog 3226/3227s and call it done. Then the "this product doesn't fit your application" warnings put me off those coils. However, because of this thread, I'm warming back up to strongly reconsider them.

A wrinkle to this is the additional talk about H&R springs I've seen here and elsewhere. Those are becoming slightly more attractive to me because they are progressive springs, which I understand the OEMs were as well. It's also nice that all 4 H&R springs are available in kit form via Tire Rack, for just over $200. (Which is similar to the Moog Rubicon combination from Rock Auto.)

The only hesitation I still have with the H&R route is, wouldn't adding them then mean I'd need longer shocks, have to extend the jounce/bump cups, etc. even if all I got was +/- 1-inch of lift front and rear? (Base-level Ranchos would supposedly handle up to 1-inch lifts. So, maybe not? I don't know.) Maybe I'd be ok, but probably wouldn't know for sure until I'd already paid and installed the things. Ah, the joys of Jeep ownership.

Anyway, please keep offering input, especially if you found something that just flat-out didn't work for you or your Unlimited/LJ.

 

[Fulton_Hogan]

There should be a Mopar tag that says 6AA I believe... If we can get Blaine to chime in he can tell you what springs to put on it to do what you want probably.

I did some internet deep dives and found other Unlimited/LJ owners who still had tags on their coils. Those threads were from pre-2010, so not current, but the most reported numbers off those coils were:

56052335AA​

56052436AA​

56052456AA​

​

The main factor in these is the 5605 prefix. Those seem to have been the Unlimited/LJ springs. I say that because of the people reporting their original springs on their Unlimiteds/LJs, they reported those numbers. More specifically, they reported the 56052335AA or the 56052436AA.

Now what any of the those original coils' load (lbs) or spring rate (in/lb) is; I have no idea. I'm making a swag here and guessing the lower the number, the lower the load and spring rate.

Maybe 2335AA was for the soft top option (which I've seen mentioned), 2436AA was the dual top option, and 2456AA was the Rubicon Unlimited. Again, all interpolation and theory at this point.

All of this has research is what ultimately lead me to starting this thread.

 

[AndyG]

Cool. I know what I do probably.... I'd get a set of stock springs and put 1 inch coil spacers under them and go for a little bit of rake and call it good.... I'm assuming through this you've measured your bucket to bucket measurements and kind of know where you are.

 

[Fulton_Hogan]

Yes, I did an initial measurement of the Jeep when I first got it. It was within the specs I've seen for a stock setup.

I'll be getting more detailed measurements when I get under it this weekend and start firming up my decision on how I'm going to proceed.

 

[Fulton_Hogan]

I've called H&R directly and they won't provide any information about their springs. Other than to tell you they are a progressive spring. That said, having installed two sets, I wouldn't hesitate to use them in your situation. The H&R springs are extremely well made and should work on your stockish LJ with no issues. If you did go that route, you could always have a set of 1" aluminum spacers in reserve. This would allow you to tune the ride height a little, if needed. See post #157 in the link. I'm planning to use them again on a TJ build I'm doing now. There are a few numbers in there for reference. Plus, Tire Rack had the best price on them I could find.

https://wranglertjforum.com/threads/a-lesson-learned—keep-it-light-and-nimble.44924/page-8

I started down this thread last night, but didn't get this far. Thanks for directly linking and for originally providing those photos.

 

[Fulton_Hogan]

What does the tag say on your rear springs?

Thursday evening I jacked up the rear, put the rear frame on stands and got to replacing my rotted out rubber jounce/bump stops. While under there, surprise of surprises, I found tags on both rear springs. (I think the fronts only have one with a tag left on them.) I gingerly pulled the driver side tag off, but left the passenger side.

The previous owner had Ziebart sprayed on the Jeep's underside, of course that coating obscured some of the numbers on the tags. I took a q-tip with a little Kroil on it and did some 'art restoration' cleaning of the removed tag and got this:

Majority of removed tag.

Best results came from a smaller bit of tag that tore off the bit pictured above.

Here's the other one still in place.

As far as I know (based on its build sheet) this Unlimited/LJ was optioned/sent as a soft top. So my theory on the 56052436AA coils being used on dual-tops seems less sure. Maybe because it was a manual transmission? Who knows at this point. Point is, I know where I started.

That left addressing the leaking passenger rear shock.

I ordered stock-height Rancho RS5000Xs for all corners. I started spraying all the shock bolts with some Free-All, and I'll alternate between that Deep Creep, and Kroil until I'm ready to attempt that work. After those are done and have had a chance to settle I'll check the coil heights and make a decision on those.

I appreciate the advice given, thanks again.

 

[winerizi]

Hi there! I’m reviving this thread.

I find myself in a similar situation, in 2024, with an LJ Unlimited. I’m looking to replace the shocks and possibly the coil springs while keeping the lift below 2 inches.

From my research, it seems like H&R springs could work, but they might not fit perfectly on the LJ. OME springs also look like a solid option, but I’m concerned the lift might end up being too high.

which coil springs did you @Fulton_Hogan end up choosing?

Thanks in advance for any advice!

 

[Fulton_Hogan]

Hi there! I’m reviving this thread.

I find myself in a similar situation, in 2024, with an LJ Unlimited. I’m looking to replace the shocks and possibly the coil springs while keeping the lift below 2 inches.

From my research, it seems like H&R springs could work, but they might not fit perfectly on the LJ. OME springs also look like a solid option, but I’m concerned the lift might end up being too high.

which coil springs did you @Fulton_Hogan end up choosing?

Thanks in advance for any advice!

I ended up getting Moog 3226 and 3227 springs. Still happy with them.

Here's where I swapped them and what they achieved (go to link to see measurements, preview cuts them off):

Post in thread 'What did you do to your TJ today?'

Apr 30, 2022

Today I did the spring swap I hadn't planned on doing, but it went well, it's done, and I'm glad I did it.

These are the original springs (left) next to the corresponding Moog 3226/3227 springs.

The fronts didn't look much thicker, but with the naked eye I could tell the new rears were thicker wire.

I wire brushed and touched up the paint as necessary. Didn't get a picture of the front progress.

So how did they do? Great, maybe good as new.

Took these in the same place and distance to try and get a fairly decent comparison.

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• Fulton_Hogan

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