Death wobble: what should I check?

[rudymags]

I was tooling along the highway at like 60 or so MPH on my '95, 2.5L, 5 speed yj when I hit a bump where the asphalt hit the joined part of repaved highway & I got the wildest, hardest, scarest, shaking & wobble like I had never had before. Scared me sos I hit my brakes to slow & settle it down.
I took the trac bars off a couple of years ago. So what do I need to check or replace on my front end??

 

[ytradio]

First thing I would replace is the horizontal stabilizer shock Or at the very least check to see if it is still good and mounted tightly.

 

[machoheadgames]

I had that at one point, would start after hitting potholes. I’m pretty sure it was worn out ball joints for me. I replaced all the tie rod ends first but I could still get it to do it if I intentionally hit bumps. I replaced ball joints and it didn’t happen again. Weirdly enough, I could look out the door and see the tires shaking back and forth as if they were turning left and right repeatedly, which is why I thought tie rod ends but they didn’t fix it. Maybe it was a combo of issues. I also had the track bars off but I went so long without track bars before the problems set in that the track bars def weren’t the issue.

 

[rudymags]

Thanks I'll see about them ball joints. What am I looking for that tells me if they are bad?

 

[machoheadgames]

Thanks I'll see about them ball joints. What am I looking for that tells me if they are bad?

Don’t really have a suggestion for that. My solution was to throw parts at it, which isn’t ideal. The way my wheels shook I thought surely it was the tie rod ends, plus mine were 25 years old so I figured why not.

The ball joints at the time were synergy brand and like 1.5 years old. So they were the next suspect to me. Absolute garbage. Meanwhile the 23 year old spicers they replaced were perfect when they replaced them. I still don’t really see how play in ball joints could be enough to get the wobble going like that, which is why I’m not really sure about testing the ball joints. Not sure any of the typical tests of looking for vertical movement will really tell anything. Hence why I decided to just throw parts and lucked out on the second try fixing it.

 

[dante2]

Jack up the front end and set it on jackstands. For tie rods grab tire at 9 and 3 o'clock and rock back and forth. Your feeling for anything that feels loose. Ball joints are at 6 and 12 o'clock rock in and out. Same thing looking for movement again. Any kind of movement that is there indicates a worn part that needs to be replaced. Youtube has a bunch of videos showing what i'm talking about. My tie rods boots are torn but I have no movement in them, ball joints are the same. Could be the original for all I know.

 

[DOWNS]

Thanks I'll see about them ball joints. What am I looking for that tells me if they are bad?

Jack up the front end. Put a lever under the tire and pry up. If you see ANY up and down movement in the ball joints, they are bad. This will show a worn ball joint long before the "grab at 12 and 6" method. If the grab at 12 and 6 method shows play, you're way past worn out into dangerously worn out territory.

Put the front end back down on a high traction surface like your driveway. Have someone sit in the Jeep and slowly saw the wheel back and forth while you closely inspect each tie rod joint for ANY side to side play. If you see any, replace that joint. Severely worn out bushings in the shackles or the rear pivot for the leaf springs can also cause issues. Honestly, the track bar helps in this regard as far as keeping the front end rigid against stuff like death wobble. Doing this with the front end on the ground will show worn parts before the "grab and 3 and 9" method, as the steering system is going to be able to exert more force on the rods than you will with your hands on the tire and the increased force required to turn the wheels on the ground will show small amount of play that you may not notice using arm strength on the tire.

Don't put too much stock in the steering stabilizer, what someone above called the "horizontal stabilizer shock". That's always the first thing people shotgun out there to replace, but you should be able to remove the steering stabilizer completely and still have a Jeep that drives fine with no death wobble. If you replace your steering stabilizer and it "fixed" your death wobble, it didn't fix anything, it's just covering up something else that's worn out. It's a band aid fix.

 

[DOWNS]

Don’t really have a suggestion for that. My solution was to throw parts at it, which isn’t ideal. The way my wheels shook I thought surely it was the tie rod ends, plus mine were 25 years old so I figured why not.

The ball joints at the time were synergy brand and like 1.5 years old. So they were the next suspect to me. Absolute garbage. Meanwhile the 23 year old spicers they replaced were perfect when they replaced them. I still don’t really see how play in ball joints could be enough to get the wobble going like that, which is why I’m not really sure about testing the ball joints. Not sure any of the typical tests of looking for vertical movement will really tell anything. Hence why I decided to just throw parts and lucked out on the second try fixing it.

The ball joint is essentially a spherical joint, just like a tie rod end. If there is up and down play there is left and right play even if you aren't able to perceive it. The forces involved with driving down a road at speed in a 4,000 lb piece of equipment is enough to get an oscillation going and at certain speeds/frequencies it basically becomes a feedback loop and gets worse and worse till you have death wobble. That's why it tends to only occur at certain speeds that may change with time as the parts become more and more worn.