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Discussion Starter · #1 ·
The back end of my JKU seems to bottom out really easily when mildly loaded and /or towing a lighter load. Lift kit is 2" Mopar lift kit. Using SumoSprings as progressive bumpstops ( works great BTW). No rear tire carrier or aftermarket bumper...yet.

I am concerned about adding the additional weight of a tire carrier, Titan gas tank, AND carrying my usual overlanding load will exacerbate the issue.

Rather than throw money at a guessing game, anyone have some thoughts? Anyone compare Mopar springs to Synergy? Do I need to get a revalve on my shocks?

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Are the sumo springs going "solid" (Do they even do that) at the right height? If not you could be bottoming out your shocks, which would spell disaster for their lifespan.
 

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Discussion Starter · #3 ·
Shocks are Fox provided with kit. Bump stop spacer provided with kit was mounted. To verify, I've slid the rubber bumpers up the shock...there is about 2" of compression available. Unless I have the wrong shocks, I don't see how the shocks could be damaged.

The sumosprings are replacement foam bumpstops that offer progressive spring rate - similar to teraflex w/o the can. They are about 3/4" longer than factory stops...and cushion the bottoming out. They don't seem to limit articulation...

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Shocks are Fox provided with kit. Bump stop spacer provided with kit was mounted. To verify, I've slid the rubber bumpers up the shock...there is about 2" of compression available. Unless I have the wrong shocks, I don't see how the shocks could be damaged.

The sumosprings are replacement foam bumpstops that offer progressive spring rate - similar to teraflex w/o the can. They are about 3/4" longer than factory stops...and cushion the bottoming out. They don't seem to limit articulation...

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Yes but those can style bumpstops at full compression are solid.

While they may be longer extended than the factory stops, if they are compressing beneath the length of the factory stops, you will bottom out your shock.

Can I see a picture of your setup. Might avoid confusion here

To clarify your bumpstops must become SOLID at a point 2" longer than the factory bumpstop cone to prevent the new shock from bottoming out. Hence the 2" bumpstop EXTENSIONS that came with the kit.

You said you were using the sumo spring as a bump stop, does that mean you replaced the factory cone with it? If not, than it's not a bump stop at all, it's a cushion...

The Teraflex hydraulic bump stops provide cushioning by dampening the strike force of the bumpstop. In the end tho, it's set to a maximum compression height designed to completely stop the suspension from compressing any further than that.
 

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Here is an industrial rocker arm at my work utilizing a hydraulic bump stop. When the arm comes down the hydraulic fluid slows its motion, providing a cushion so the machine doesn't "slam" into resting position.

You can also see the real, solid hard, physical bumpstops next to it that prevent the hydraulic bumpstop from completely bottoming it out and damaging itself.

So what I am saying to you is that the sumo spring needs to act as a cushion, not as an actual bump stop
 

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That was the extension end of our machine. Let's show the compression end. You can see how in these pictures the white hydraulic "bumpstop" is a cushion.

As we reach max compression of the shock, the hydraulic cushion starts slowing the movement down. Until the rocker arm (axle) comes down on the two solid black rubber bumpstops at rest
 

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Discussion Starter · #7 ·
Sorry for not responding to the thread...life gets in the way sometimes.


So I rcvd a PM from a fellow jeeper that is having problems with his Mopar lift... and since I posted this, I have developed some other symptoms on the bottoming out situation: see below.


Kennedyb said:
I have the same lift and mine bottoms out in the rear, on the driver side. I’ve found several others with the same problem but no solutions. We’re you able to figure yours out?
Interesting...I was reading about this today in the Mopar Lift thread. My problem is the passenger side. It became worse with time.

I never did get it figured out as had other priorities (kids, house, job, etc). I've been delaying some PM, but can no longer ignore my rear brakes and have random ABS/ESP issues along with false ABS firing. ...I have NO parking brake and on an manual, that can be problematic...ha.

Anyhow, I plan to swap the springs from driver to passenger to see if that 'moves' the problem. If not, I'm going to try the shocks...there is far to much dip in the passenger side for it to make any sense. At first I thought it was track bar, but I raised the rear track bar to the upper hole and installed a superlift adjustable to center the axle.

The lift also seems to have settled ALOT with time. I'll measure it today and post my results. My plan is to tackle the rear axle rebuild this week...
 

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Mine seems to do the same thing on the driver side as well. Very weird. I put 5 people in the back, and then had someone 150 lbs stand on the bumper and bounce it trying to figure out for sure that it was bottoming out and not some other part getting in the way, I could not replicate it. Even with that added weight and the bouncing it still was far from bottoming out.



Mine will do it on the speed humps in my neighborhood but not always...very weird.
 
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