rear springs

craneman · **Posted:** Wed Feb 26, 2020 9:27 am

looking for a set of JBA rear springs.
Help!!!!!!

flash7210 · **Posted:** Wed Feb 26, 2020 10:46 am

Why specifically JBA rear springs?

OME 2947 springs will work.
I used Moog 81041 with half a coil cut off the top.
If you need more lift than what those can provide, double up your top rubber isolators.
And get some hockey pucks for your bump stops.

You should also consider getting the IRO rear upper control arm. WWdiesel can build you a proper mount for it.

craneman · **Posted:** Wed Feb 26, 2020 10:59 am

Thanks for the info. will take a look at the ome springs. never gave that a thought. was lucky to get a complete JBA front set up brand new from a guy locally. I was just trying to match the front but its not a game breaker. want to get this lifted a couple of inches so I can go with larger tires.
will look into the rear end material also. appreciate all the help.

craneman · **Posted:** Wed Feb 26, 2020 11:16 am

cant seem to find WWDIESEL. are they still in business?

WWDiesel · **Posted:** Wed Feb 26, 2020 12:04 pm

craneman wrote:

cant seem to find WWDIESEL. are they still in business?

Custom Mounts in stock that allows the Heavy Duty IronRock Rear Upper Control Arm to be mounted and used on the Jeep KJ.
Red or Black Powder Coat
See this:> viewtopic.php?f=169&t=90867
also
Secondary Fuel Filter mounts/kits in stock.
viewtopic.php?f=169&t=90868

flman · **Posted:** Sun Aug 02, 2026 1:20 pm

I think I am due for rear springs, I had sand bags in the back for a couple of years, and it feels like I am hitting the stops on some bumps going down the highway, also the springs are loose when I have it on a lift with the rear axle hanging. One more part for the jeep. :jester:

WWDiesel · **Posted:** Sun Aug 02, 2026 11:17 pm

How's the boomerang bushings and rear upper ball joint? Those weak rubber bushings at the body end of the boomerang tend to get real weak fast and allow a thumping noise especially when the transmission upshifts or downshifts. This thumping noise can be heard real loud inside the cabin since the upper control arm (boomerang) bolts directly to the underside of the cabin, not the frame, right under the rear seat area.
The super heavy duty IronRock rear upper & lower control arms are the best you can buy to upgrade the rear suspension and make it bullet proof.

As to the springs, upgrading to the IronMan 4X4 America springs, front and rear, or the OME springs is your best choices.
Neither is cheap, but if you want quality, you have to pay for it.
https://www.ironman4x4.com/collections/coil-springs

The rear springs being a little loose when you have the vehicle on a lift with the rear axle at full droop is normal.
If you want a good ride and good handling, get the Bilstein shocks/struts front and rear, they are some of the best there is on the market.

Struts/Shocks:
Bilstein Brand: 4600 Heavy Duty (B6)
Part Number Position
24-139168 Front
24-139175 Rear

flman · **Posted:** Mon Aug 03, 2026 8:47 am

WWDiesel wrote:

How's the boomerang bushings and rear upper ball joint? Those weak rubber bushings at the body end of the boomerang tend to get real weak fast and allow a thumping noise especially when the transmission upshifts or downshifts. This thumping noise can be heard real loud inside the cabin since the upper control arm (boomerang) bolts directly to the underside of the cabin, not the frame, right under the rear seat area.
The super heavy duty IronRock rear upper & lower control arms are the best you can buy to upgrade the rear suspension and make it bullet proof.

As to the springs, upgrading to the IronMan 4X4 America springs, front and rear, or the OME springs is your best choices.
Neither is cheap, but if you want quality, you have to pay for it.
https://www.ironman4x4.com/collections/coil-springs

The rear springs being a little loose when you have the vehicle on a lift with the rear axle at full droop is normal.
If you want a good ride and good handling, get the Bilstein shocks/struts front and rear, they are some of the best there is on the market.

Struts/Shocks:
Bilstein Brand: 4600 Heavy Duty (B6)
Part Number Position
24-139168 Front
24-139175 Rear

I put in a new boomerang when I did the rear differential.

I am talking loose that I can spin them around, is that normal loose?

WWDiesel · **Posted:** Mon Aug 03, 2026 1:17 pm

The stock factory OEM boomerang is pure junk! It is made out of thin pressed metal and the two rubber bushings at the body end attachment points under the rear seat area on both sides are very soft and allow way too much movement. That is why I always recommend the IronRock control arms; their rubber bushings along with the Heim joint on top of the rear axle are very solid and don't allow excess movement of the rear axle during acceleration, de-acceleration, and up and down gear shifts. :wink:

As to the rear springs; the factory springs were a little loose just like you described with the rear axle a full droop on a lift supported by the factory shocks. I could spin & shake the rear springs by hand with little effort.
When I installed the new IronMan 4X4 Offroad springs in the rear, they were not loose like the factory springs. They were longer than the factory springs.
I actually had to use a jack to lift/force the rear axle up high enough to attach the new Bilstein Shocks to the axle housing.

Below is a picture of the old factory spring next to the new IronMan 4X4 spring so you can clearly see the difference in lengths.

flman · **Posted:** Tue Aug 04, 2026 1:11 pm

Like I said, just a an old A to B Jeep, not doing any serious upgrades, maybe when the highway says "Dip" I can expect to hit the stops.

WWDiesel · **Posted:** Tue Aug 04, 2026 4:53 pm

A set of good heavy duty gas charged shocks will make a world of difference in handling and reactions to dips even with the aged factory springs. :wink:

rear springs

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