Rock Krawler Upper Spring Isolator Modification (4xe/392/Diesel)

[KebertXela]

I recently installed a 3.5" Rock Krawler X-Factor "No-Limits" suspension system on my 2021 Rubicon 4xe. Everything went pretty smoothly following the instructions for the JL X Factor Series Mid Arm found on Rock Krawler's website. However I ran into one very noticeable issue with the Front Springs bowing badly inward towards the frame. Searching the forums for a solution, I've seen other people with this issue - particularly those with 4xe, 392, and Diesel Wranglers - but could not find any detailed solution.

Contacting @Rock Krawler Suspension, they quickly provided a video explaining a fix by modifying the upper spring isolators.
Link to video

Not really sure why this information isn't provided in the instructions, which haven't been updated since June 2021.

[One other big significant note for 4xe owners: You are not able to reroute the parking brake cables under the cross member. Jeep redesigned the paneling (at least on the 4xe) which makes it impossible to access the parking brake cables from the front side of the cross member. You will need to get a parking brake cable extension kit like the one Teraflex offers or longer cables.]

I figured I'd document this in case anyone else is in my position in the future.

Before Pics:

First, after lifting the jeep and removing the tires, make sure to disconnect the following:

• Drag Link (at the steering knuckle)
• Track Bar (at the Frame mount) (found this easier as the axle joint was a pain to get in the first time)
• Remove both sway bar links
• Remove Shocks from bottom mounts
• Electric Locker connector
• Axle Disconnect connector
• Diff breather tube

Note: If you don't have access to a lift and are using a floor jack and jack stands, you will need to rise the jeep frame pretty high in order to drop the front axle enough to get these springs (3.5") out.

Next, using a paint marker, I marked the isolator, spring, and bump stop so I have a reference for when I rotate the isolator and put everything back.

Now, unbolt the bump stops and remove the springs and isolators.

To modify the isolators, I used a grinder with a 80 grit flap disc and ground down the edges until they were pretty flush with the existing spring grove. Do this to both isolators.

Finally, make a mark on the opposite side of the isolator (180º) from your first mark to allow you to line it up with the mark on the spring and bump stop.

Reinstall the springs and isolators.

Reinstall everything else as you compress the springs:

• Bump stops
• Shocks at bottom mount
• Drag Link (at the steering knuckle)
• Track Bar (at the Frame mount)
• Electric Locker connector
• Axle Disconnect connector
• Diff breather tube
• Both sway bar links
• Wheels

Once the Jeep is sitting on its own weight, torque all reinstalled mounting bolts to spec.

After Pics:

Springs are now sitting straight!

This modification should be a temporary fix, Rock Krawler is supposedly working on a new upper isolator (probably similar to the one MetalCloak offers) that will correct the bow and you won't need to do this modification anymore.

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[A.leec34]

Has there been a release of a correction part I installed the mopar diesel 2in lift on my 23 jlur 3.6 and both front springs bow inward and contact the frame when flexed I’m willing to modify the upper pad but would prefer to buy a correction pad instead ?

 

[Roky]

Has there been a release of a correction part I installed the mopar diesel 2in lift on my 23 jlur 3.6 and both front springs bow inward and contact the frame when flexed I’m willing to modify the upper pad but would prefer to buy a correction pad instead ?

https://rockkrawler.com/front-neutral-spring-isolator-jl-jt/

If you’re using Mopar lift springs then you need to use oem upper isolator since they are modeled after the oem springs… you can get the RK lower spring perches to help with the bowing…… if it’s hitting the frame when stuffed then that’s normal…the spring will bow inward when fully compressed, you can add more bump stop to help it not bow as much……

 

[A.leec34]

https://rockkrawler.com/front-neutral-spring-isolator-jl-jt/

If you’re using Mopar lift springs then you need to use oem upper isolator since they are modeled after the oem springs… you can get the RK lower spring perches to help with the bowing…… if it’s hitting the frame when stuffed then that’s normal…the spring will bow inward when fully compressed, you can add more bump stop to help it not bow as much……

I went ahead and ordered the neutral top isolator I think that will help a lot cause mine is made thicker on the outside which would further the Bowing so hopefully this helps

 

[Roky]

I went ahead and ordered the neutral top isolator I think that will help a lot cause mine is made thicker on the outside which would further the Bowing so hopefully this helps

The neutral isolator is for springs that the tail (end) of the spring is flush with the last coil…( RK, MC, etc…) The Mopar lift springs the tail of the spring sits a little higher that’s why the oem isolators are tapered…… if your spring is bowed at ride height then you need the RK lower perches to help with that….. if the springs are straight at ride height and only bow inward when compressed then that’s normal…….does it look like this…..?

 

[A.leec34]

The neutral isolator is for springs that the tail (end) of the spring is flush with the last coil…( RK, MC, etc…) The Mopar lift springs the tail of the spring sits a little higher that’s why the oem isolators are tapered…… if your spring is bowed at ride height then you need the RK lower perches to help with that….. if the springs are straight at ride height and only bow inward when compressed then that’s normal…….does it look like this…..?

The neutral isolator is for springs that the tail (end) of the spring is flush with the last coil…( RK, MC, etc…) The Mopar lift springs the tail of the spring sits a little higher that’s why the oem isolators are tapered…… if your spring is bowed at ride height then you need the RK lower perches to help with that….. if the springs are straight at ride height and only bow inward when compressed then that’s normal…….does it look like this…..?

Here’s pics of mine sitting flat and pics flexed

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