Bump steer help

[Spencer]

I need some help chasing down the bump steer in my 2021 JLUR. Driving between 30-50mph and hitting a bump or hole in the road makes the steering wheel wobble for 1-2 seconds.

After having someone turn my steering wheel back and forth between 10-2 o’clock and following Planmans video of diagnosing I’m finding a little up/down movement between the stock drag link and pitman arm.

I’ve read a dozen articles and seems like there is nothing in particular that is causing this. But everyone had something wrong and I have to keep troubleshooting until it’s gone.

History of the mods to the Jeep in order:

1- MOPAR lift with adjustable Track bars
2-EVO front bumper with Warn 12k winch
3-Synergy Steering stabilizer relocate with Synergy tie Rod.
4-3/4” inch front coil spacers to level out the Jeep.
This is about when the wobbles/bump steer started happening.
5-Clayton upper and lower control arms set to Claytons specs for their 2.5” lift. Caster looks like it’s at 6 degrees.

I have a Synergy drag link and Fox TS steering stabilizer on order and wanted to install that before taking it in for an alignment.

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[Crawldad]

that's not bump steer. that's death wobble.

bump steer is steering direction change when hitting a bump/hole/etc.

death wobble is a full oscillation after hitting a bump/seam in the road/etc.

https://viciousoffroad.com/n-20-taking-the-wheel-steering-bump-steer-and-death-wobble.html

two main items have helped me overcome death wobble:
(brand is not as important as the combination):
sector shaft brace and HD adjustable trackbar.

i use the synergy units. others use smart steer or other brands.

also the steering box can be damaged if you have been experiencing this for a long time. the sector shaft where the pitman arm connects gets less and less tight. the sector shaft brace can prevent this damage and prevent death wobble to begin with.

 

[Spencer]

that's not bump steer. that's death wobble.

bump steer is steering direction change when hitting a bump/hole/etc.

death wobble is a full oscillation after hitting a bump/seam in the road/etc.

https://viciousoffroad.com/n-20-taking-the-wheel-steering-bump-steer-and-death-wobble.html

two main items have helped me overcome death wobble:
(brand is not as important as the combination):
sector shaft brace and HD adjustable trackbar.

i use the synergy units. others use smart steer or other brands.

also the steering box can be damaged if you have been experiencing this for a long time. the sector shaft where the pitman arm connects gets less and less tight. the sector shaft brace can prevent this damage and prevent death wobble to begin with.

Thanks for the help. The wobbles have only been around for the last 500 miles. I’ve read that the sector shaft brace can solve this issue too. Guess I need to warm up the credit card again.

 

[Jeep&dogs]

Just curious did you drive it before the 3/4 spacers were installed and if so did you notice the wobble?

 

[Spencer]

Just curious did you drive it before the 3/4 spacers were installed and if so did you notice the wobble?

The MOPAR lift was installed from day one. When the lift was fresh and not settled it had a very “flighty” feel on the road imperfections.

After the suspension settled and after I put a heavy bumper and winch on the Jeep the Jeep drove the best. However I don’t like the look of the front end being lower than the back. (2” difference)

Putting 3/4”coil spacers brought back the flighty feel and a little more due to the added weight.

I’m currently looking at Synergy springs to replace the MOPAR springs along with the spacers. I’m thinking of ordering the 3” front springs with 2” rear springs for a level stance with the added weight in the front.

 

[limeade]

The "flighty" feel you describe is probably due to low caster numbers. Adjust your control arms some more to get closer to 7 degrees. That should help. Once you get your new drag link, get an alignment to ensure your total toe is within spec. I personally like 1/16" - 1/8" total toe in.

I have to disagree with @Crawldad on his diagnosis of death wobble. From what you describe, it is NOT death wobble, you have a shimmy or such which is occurring in a certain speed range and under specific conditions.

With death wobble, the "death" part is accurate in that you very much believe your Jeep is going to flip over and the only way to get it to stop is to slow to almost a complete stop.

These shimmy's can be caused by any or or number of front end steering/suspension issues. The costs can really add up by throwing parts at it.

Once you take care of the caster and total toe, get under the front while someone else slightly turns the steering wheel looking for unwanted movement at each and every steering and suspension joint. Also check the condition of your ball joints. The stock units are notorious for wearing out very quickly, especially with larger/heavier wheels and tires.

My guess is your ball joints are bad, but that's just a guess based upon what you're describing and have done to your Jeep.

Since you have a 2021, I'm going to assume you have the steel steering gear box, so we can "probably" rule out a bad steering box.

 

[Spencer]

The "flighty" feel you describe is probably due to low caster numbers. Adjust your control arms some more to get closer to 7 degrees. That should help. Once you get your new drag link, get an alignment to ensure your total toe is within spec. I personally like 1/16" - 1/8" total toe in.

I have to disagree with @Crawldad on his diagnosis of death wobble. From what you describe, it is NOT death wobble, you have a shimmy or such which is occurring in a certain speed range and under specific conditions.

With death wobble, the "death" part is accurate in that you very much believe your Jeep is going to flip over and the only way to get it to stop is to slow to almost a complete stop.

These shimmy's can be caused by any or or number of front end steering/suspension issues. The costs can really add up by throwing parts at it.

Once you take care of the caster and total toe, get under the front while someone else slightly turns the steering wheel looking for unwanted movement at each and every steering and suspension joint. Also check the condition of your ball joints. The stock units are notorious for wearing out very quickly, especially with larger/heavier wheels and tires.

My guess is your ball joints are bad, but that's just a guess based upon what you're describing and have done to your Jeep.

Since you have a 2021, I'm going to assume you have the steel steering gear box, so we can "probably" rule out a bad steering box.

I totally agree. I had full blown death wobble in my old land cruiser. It’s not there.....yet =)

Your suggestion is exactly my plan. Thanks for reassuring me I’m on the right track.

Also, I did get under the Jeep with someone moving the steering wheel from 9-3 o’clock and didn’t notice any movement from the steering box. However I did find some movement between the drag link and the pitman arm.

 

[Spencer]

Been reading numerous threads trying to figure out how to cure the wobbles and I have found this thread to have the solutions I needed to fix the wobbles.

https://www.jlwranglerforums.com/forum/threads/early-onset-death-wobble-help.47763/

Let me back up and give a little history in order of progression.
-New 2021 JLUR
-Mopar lift
-37's
-Metal Cloak front and rear track bars
-Synergy Tie rod
-Steering stabilizer relocation kit by Synergy. Still using the stock stabilizer.
-3/4" coil spacers on the front to compensate for the added weight of the winch and bumper to level out the Jeep

(THIS IS WHEN MY WOBBLES STARTED BEING MORE PRONOUNCED)

-Clayton upper and lower control arms installed. Caster set to 7 degrees. (steering wheel tries to straighten out after a turn more so than before and the Jeep tracks better going down the road, but still have the wobbles)
-Synergy Drag link. Since there was a little play between the pitman arm and stock drag link. (no change in wobbles)
-Rancho track bar bracket reinforcement. Cheap $90 mod for insurance and stronger foundation for the steering box even though no movement was coming from the steering box or the track bar.(no change in wobbles)
-checked torque on axle/steering components multiple times. (no change in wobbles)
-used the method shared on this thread to set the toe and noticed the toe was set (by me) to about 3/4" toe in. BAD! Changed the toe to 1/32" toe in and most of the wobbles were gone.
-Installed the Fox ATS steering stabilizer and set it to 17 out of 24 soft to firm settings. WOBBLES are all gone!

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