BUMP Steer

[LSguy]

had a look at the ball joints for fun. 1 of the 2 cotter pins was a bitch. With cotter pins, it always seems if you don’t get the perfect “bend back to straight” on the first try you are stuck messing with it forever lol. Anyhow, the torque was fine. I was able to nudge the bottom to get it at 35lbs but not even enough to change the slot the cotter pin was through so I’m sure it was fine. Top joint was a total pain to get the right angle to get a torque wrench on with an articulating extension with the axel still there. In any event, I checked just the side that seems to initiate the shimmy on impact as to not create extra work yet. And my bump steer/ shimmy may even be excessive to say 1-2 seconds. It’s more like 2-3 shimmy’s of the wheel that takes place in under 1 second (and never a death wobble scenario).

I've dealt with too many cotter pins in my career to ever attempt saving one to reuse. Easiest removal method:

Push the head back as far as you can and snip it with some heavy side cuts. Take a pair of channel locks and grab the legs one at a time, rotate the pliers 90 degrees against the castle nut.

Insert new cotter pin when finished.

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[Terminex]

That's not a great angle, you need to take it from the bottom front, so we can actually see the track bar's alignment without perspective coming into play.

Agree the angle sucks, but with the front bumper that has an integrated skid, that is the only angle i could take it from, other than directly underneath looking up.

 

[DexterJeeper]

I'm so glad I found this thread. I have a few friends with modified JLs and none have the same shimmy/mini-death wobble issue that I've been living through. Like others, the shimmy developed with the factory front end after 10k miles or so (I did put on the mopar 2" lift at the time with 37's right when I got the Jeep). When I hit a hole or bump at 35-45MPH with my passenger tire, it starts shimmying. If I hit it just right, it won't stop oscillating until I slow all the way down.

I'm at 36k now and have changed out the whole front end to Synergy, added a sector shaft brace, did the steering box TSB. I've even swapped out all my suspension bits to the 3.5" Metalcloak GC. Yet it's still there. I live about an hour from Ken's Kar Kare (Dr. Death Wobble) in Fowler, MI and have taken my Jeep to him. After checking absolutely everything, he changed the toe from slightly in to slight out and advised that I disable my ESteer through the Tazer. NONE of that made any difference. His explanation was JL's are just super sensitive to geometry changes.

I have now ordered the Synergy front track bar relo kit. My theory is hitting the passenger front creates a big enough bump steer that it triggers a mini death wobble. The same thing doesn't happen when I hit the driver front tire. If my theory is wrong, I guess I'm going to a redneck ram as a last resort.

 

[Roky]

I'm so glad I found this thread. I have a few friends with modified JLs and none have the same shimmy/mini-death wobble issue that I've been living through. Like others, the shimmy developed with the factory front end after 10k miles or so (I did put on the mopar 2" lift at the time with 37's right when I got the Jeep). When I hit a hole or bump at 35-45MPH with my passenger tire, it starts shimmying. If I hit it just right, it won't stop oscillating until I slow all the way down.

I'm at 36k now and have changed out the whole front end to Synergy, added a sector shaft brace, did the steering box TSB. I've even swapped out all my suspension bits to the 3.5" Metalcloak GC. Yet it's still there. I live about an hour from Ken's Kar Kare (Dr. Death Wobble) in Fowler, MI and have taken my Jeep to him. After checking absolutely everything, he changed the toe from slightly in to slight out and advised that I disable my ESteer through the Tazer. NONE of that made any difference. His explanation was JL's are just super sensitive to geometry changes.

I have now ordered the Synergy front track bar relo kit. My theory is hitting the passenger front creates a big enough bump steer that it triggers a mini death wobble. The same thing doesn't happen when I hit the driver front tire. If my theory is wrong, I guess I'm going to a redneck ram as a last resort.

Put an angle finder on top of track bar then on drag link , see how far off the two numbers are. Be precise on where you put it , top dead center, if you’re off a little it will give false reading from bar to bar. I’m assuming your front axle is centered ?

 

[Jeep&dogs]

I'm so glad I found this thread. I have a few friends with modified JLs and none have the same shimmy/mini-death wobble issue that I've been living through. Like others, the shimmy developed with the factory front end after 10k miles or so (I did put on the mopar 2" lift at the time with 37's right when I got the Jeep). When I hit a hole or bump at 35-45MPH with my passenger tire, it starts shimmying. If I hit it just right, it won't stop oscillating until I slow all the way down.

I'm at 36k now and have changed out the whole front end to Synergy, added a sector shaft brace, did the steering box TSB. I've even swapped out all my suspension bits to the 3.5" Metalcloak GC. Yet it's still there. I live about an hour from Ken's Kar Kare (Dr. Death Wobble) in Fowler, MI and have taken my Jeep to him. After checking absolutely everything, he changed the toe from slightly in to slight out and advised that I disable my ESteer through the Tazer. NONE of that made any difference. His explanation was JL's are just super sensitive to geometry changes.

I have now ordered the Synergy front track bar relo kit. My theory is hitting the passenger front creates a big enough bump steer that it triggers a mini death wobble. The same thing doesn't happen when I hit the driver front tire. If my theory is wrong, I guess I'm going to a redneck ram as a last resort.

Are you saying it started when you first put the lift on or it has now started after you hit 36k?

 

[DexterJeeper]

Are you saying it started when you first put the lift on or it has now started after you hit 36k?

It started with all the factory parts BEFORE I put my lift on. Also as an update, I installed the Synergy FTB relo kit. It didn't fix my issue. The change in roll center did make the Jeep feel more "flat" when going over bumps and doing sharp turns though. Back to the drawing board....

 

[KNN]

yeah, Teraflex offers 2 different front brackets based upon the height of your lift.

Any issues getting the bracket on? The first bracket I bought came w/ a welded nut and the M14 bolt would NOT fit. It felt like I was just stripping it so I bought a second bracket and the same thing happened. I got the 4” version and it looks like it places my TB/DL angles much more parallel.

The Teraflex video shows it w/ a flag nut but both brackets I have came w/ a welded nut.

 

[Terminex]

Any issues getting the bracket on? The first bracket I bought came w/ a welded nut and the M14 bolt would NOT fit. It felt like I was just stripping it so I bought a second bracket and the same thing happened. I got the 4” version and it looks like it places my TB/DL angles much more parallel.

The Teraflex video shows it w/ a flag nut but both brackets I have came w/ a welded nut.

I used the 2.5/3.5” bracket. No welded nuts on that one. 2 of the bolts have normal nuts, and the 1 bolt that mounts on the back side of the bracket has a flag nut.

what size lift do you have?

 

[Hucke_250]

@KNN are you running a factory or aftermarket track bar? Did this bracket fix the bump steer you had?

 

[KNN]

I used the 2.5/3.5” bracket. No welded nuts on that one. 2 of the bolts have normal nuts, and the 1 bolt that mounts on the back side of the bracket has a flag nut.

what size lift do you have?

I’m on a Clayton 3.5” lift. I contacted @TeraFlex and they told me the brackets raise the TB the same height but the 4” moves it right about 1/2”. So I went with 4” vs 2.5/3.5” to avoid having to drill two new holes. I already drilled one for my Clayton steering stabilizer bracket. I have an adjustable Clayton TB so I’ll adjust it as needed to dial everything in.

@TeraFlex any tip getting the m14 bolt to fit the welded nut?

@KNN are you running a factory or aftermarket track bar? Did this bracket fix the bump steer you had?

I’m using a Clayton adjustable TB. I’ll report back if the bracket fixes the bump steer.

 

[KNN]

My bracket had the wrong threaded nut welded on the bracket. Teraflex shipped me a new one.

M14-2.0

M14-1.5

Explains why it didn’t fit.

 

[KNN]

@KNN are you running a factory or aftermarket track bar? Did this bracket fix the bump steer you had?

It got my bars more parallel but it did not fix my bump steer. The hunt continues….

 

[Hucke_250]

It got my bars more parallel but it did not fix my bump steer. The hunt continues….

Thanks for the update. I couldn’t find it but are you running a flipped drag link?

 

[KNN]

I’m not. Still under knuckle. I was seriously considering going flipped and relocating TB using steer smarts but consensus was not to go flipped. My bars are very parallel now but I’ve clearly got bump steer going on.

 

[word302]

I’m not. Still under knuckle. I was seriously considering going flipped and relocating TB using steer smarts but consensus was not to go flipped. My bars are very parallel now but I’ve clearly got bump steer going on.

The drag link and track bar are parallel from the factory. You don't want to move one without moving the other. What you had before relocating your track bar mount was not bump steer. You introduced bump steer by moving one bar without moving the other.

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