YJ Death Wobble?? (Fun video included) - JeepForum.com

 
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post #1 of 13 Old 10-06-2013, 11:54 AM Thread Starter
rambo3489
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YJ Death Wobble?? (Fun video included)

Alright men recently found out I have some death wobble. I have spent some time tightening everything up shackles are good and tight making sure I have no play at any joints. I originally thought my shackles were swing side to side causing it but found this not to be true from the video. I also moved my drag link to a better angle thinking that was the cause of my problems. But that was not the case. So I just wanted to post my little video up here for yall to look at and give me some input. I have my suspicions on what is causing it but wanted to hear from everyone first.

The only noticeable death wobble starts at 3:00 mins. But feel free to take the whole ride along from under the YJ.

http://www.youtube.com/watch?v=3qRvM...ature=youtu.be

Here are some geometry pics








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post #2 of 13 Old 10-06-2013, 02:16 PM
coolin4u
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Actually is pretty noticeable at each of the harder bumps,i will be subscribed as i want to upgrade my steering
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post #3 of 13 Old 10-06-2013, 04:24 PM
timatoe
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I noticed it right around the 1:00 mark and again obviously about 3:20 or so. Any idea about how fast you were going there? When was the last time you had the tires balanced?

I'm not seeing weird movement in the suspension.

Mine was doing the same thing only between 35 and 45 mph, not straight but at that speed hitting any bumps. Moved the front tires to the rear and it went away. Still haven't taken them in from balancing, but that was causing mine.

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post #4 of 13 Old 10-06-2013, 04:35 PM
Tom95YJ
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I am thinking the issue is an out or round tire or wheel

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post #5 of 13 Old 10-06-2013, 04:39 PM
95YamJam
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Whats your caster angle set at. Might be too +, also having your draglink above your tie rod connecting at that spot would not help for sure. If you connect the draglink to the tie rod it needs to be in the same plane as the tie rod. So basically move it closer to the knuckle and put it in line with the tie rod(behind it). Or connect it to the same point above the tie rod link right at the knuckle.(high steer knuckle style.

My guess is the tie rod/ draglink connection point.

My build: http://www.jeepforum.com/forum/f22/95-yam-project-1527472/?highlight=
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post #6 of 13 Old 10-06-2013, 04:46 PM
xeroid81
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Your steering linkage rod looks awfully close to your spring pack,possibly due to the boomerang shackles,but I think it would be more helpful to mount the camera in front though.I thought I heard some metal to metal contact during flex but I could be wrong.I watched it three times but it comes on so fast it's hard to catch what happened.Do you run a steering damper for larger than stock tires? rubber mass in large tires is not symmetrical around the whole tire. The larger the tire the more it becomes a factor thus the reason for balancing ALL wheels. I'm assuming you've already found the culprit. Care to share your findings or is this a test?
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post #7 of 13 Old 10-06-2013, 05:06 PM Thread Starter
rambo3489
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Could be an out of balance tire. I am running beads in them. I get a little shimmy at 65+ but other than that there smooth. I did notice that one of my tires looks a bit out of round. When rotating it while up in the air I could see it go up and down slightly. Maybe 1/4". I cracked the lip on my aluminum wheel a few weeks back. Am unsure if that would cause the wheel to go out of round?

The tie rod/drag link connection worried me a little as well. Mainly because it has a bit of rotational play due to the nature of the rod ends on my knuckles. I will add that this problem seems to have been made worse when I replaced my tie rod heims. My old ones I ground flat so this rotational play would be removed. Only problem with this is that they were binding up when turning due to the knuckle paths not being symmetrical. (my friend had just sheared his heim for this exact reason) I can and will put the old ones on and see if this fixes the issue. If it does the drag link will be moved on top of the knuckle.

I'll try swapping tires front to back. These were on the rear for my last technical wheeling trip. So they did take more abuse. Maybe I did bend a wheel.

I can post another video from the front in a week or two when I get my gopro. (a cell phone taped up there wouldn't show much)

Also I might add that my steering box was tightened today with no benefit.

Thanks for the ideas guys. Keep um coming. I can look into each issue addressed independently to really nail down the root of my problem.

89 YJ.. My first jeep and I won't let it go. ▀||||▀

Current Project: None... I disgust myself.

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post #8 of 13 Old 10-06-2013, 06:10 PM
YJames90
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Quote:
Originally Posted by rambo3489 View Post
Alright men recently found out I have some death wobble. I have spent some time tightening everything up shackles are good and tight making sure I have no play at any joints. I originally thought my shackles were swing side to side causing it but found this not to be true from the video. I also moved my drag link to a better angle thinking that was the cause of my problems. But that was not the case. So I just wanted to post my little video up here for yall to look at and give me some input. I have my suspicions on what is causing it but wanted to hear from everyone first.

The only noticeable death wobble starts at 3:00 mins. But feel free to take the whole ride along from under the YJ.

http://www.youtube.com/watch?v=3qRvM...ature=youtu.be

Here are some geometry pics





Is that a steering box streathening bar?

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post #9 of 13 Old 10-06-2013, 06:28 PM
95YamJam
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Quote:
Originally Posted by YJames90 View Post

Is that a steering box streathening bar?
Yes. I have one I made that looks identical.


Argh... I didn't even think about a steering stabilizer. As little as you have that may help..

My build: http://www.jeepforum.com/forum/f22/95-yam-project-1527472/?highlight=
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post #10 of 13 Old 10-06-2013, 07:21 PM
timatoe
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Quote:
Originally Posted by 95YamJam View Post
Yes. I have one I made that looks identical.


Argh... I didn't even think about a steering stabilizer. As little as you have that may help..
It will mask it, it won't help it or fix it.

Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
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post #11 of 13 Old 10-06-2013, 07:53 PM Thread Starter
rambo3489
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I figured it out!!

It was the heim joints on the tie rod. The ones I didn't grind flat. Once I put the old ones on that were grinded flat my problem seemed to go away. The rotational movement as small as it was (1/16 of a turn) was causing some type of oscillation giving me the death wobble. Looks like I'll be building a new steering linkage. One where the draglink goes all of the way to the knuckle. AND upgrading to 1 3/4" tubing.

Adding a stabilizer is a last resort for me personally.

89 YJ.. My first jeep and I won't let it go. ▀||||▀

Current Project: None... I disgust myself.

<a href="http://www.jeepforum.com/forum/f22/my-yj-build-adventures-thread-1356941">BUILDING THE YJ MY WAY</a>
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post #12 of 13 Old 10-06-2013, 07:55 PM Thread Starter
rambo3489
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Quote:
Originally Posted by YJames90 View Post
Is that a steering box streathening bar?
Yea I bought mine. I know I know it's against my religion. But I got the MORE one for $20.

89 YJ.. My first jeep and I won't let it go. ▀||||▀

Current Project: None... I disgust myself.

<a href="http://www.jeepforum.com/forum/f22/my-yj-build-adventures-thread-1356941">BUILDING THE YJ MY WAY</a>
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post #13 of 13 Old 10-06-2013, 08:38 PM
timatoe
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Quote:
Originally Posted by rambo3489 View Post
But I got the MORE one for $20.
I'd buy it too for that price.

Quote:
Originally Posted by George Orwell
We sleep safe in our beds because rough men stand ready in the night to visit violence on those who would do us harm.
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