Death Wobble Problems

[flywaterguide]

Death Wobble Problems -

As I’ve posted before, my jeep’s having death wobble problems. It can happen at any speed over about 30 to 35 mph. It usually happens when one front tire hits a bump and the other does not, like hitting a pothole or manhole cover, for example. It gets so violent, that I have to slam on the brakes and slow the jeep down to 10 mph. or less.

I’m running a Full Traction 4� kit. A few months ago, since the FT springs were sagging so bad, I replaced all four springs with RE 4.5� springs. I also put 35� MTR’s on.

Over the last few months I’ve had the jeep aligned 3 or 4 times. I’ve also had the tires balanced and re-balanced.

Yesterday, as best we could (my kid and I), we measured the track bar for centering. It looked OK.

I am now thinking that it is a caster problem. Here’s why – when I took off my old tie rod and drag link, I noticed that the end of the tie rod, where it connects to the drag link, was rubbing on the steering stabilizer bracket on the axle. Next, my front coil springs rub on the bump stops when I’m flexing. I’ve read that with proper caster angle, that your steering should have some amount of “returnability�. Meaning that when you turn the steering wheel to the left or right, once you’ve made the turn, it should return back to straight. I don’t know if my jeep does that or not, I haven’t really thought of it, but I’m going to take it for a quick drive and see what happens. Just eyeballing things, it looks like everything is rotated a bit forward, which caused the stabilizer bracket to rub on the tie rod end and cause the other noted problems.

Assuming my caster angle is wrong, how do I verify it and what do need to correct it?

Any ideas, suggestions, thoughts, or comments are greatly appreciated!

Thanks in advance,

Flywaterguide

[igofshn]

Death wobble is caused by the trac bar. Bump steer is caused by poor caster. Longer lower arms should solve the problem.

[H8PVMT]

Death wobble is caused by the trac bar. Bump steer is caused by poor caster. Longer lower arms should solve the problem.

Yeah what Al said. I have a 4" lift and after getting the longer lower arms and adjusting my track bar it went away. I noticed my axle was off centered a little less than quarter of an inch. I fixed that and everything was gravy.

Oh yeah and I honestly couldn't tell you how to do the caster, I just thought mine looked good and hooked it up.

[igofshn]

Caster really cannot be adjusted, except you can use adjustable control arms and it will rotate the axle back closed to factory specs.

[flywaterguide]

Yeah what Al said. I have a 4" lift and after getting the longer lower arms and adjusting my track bar it went away. I noticed my axle was off centered a little less than quarter of an inch. I fixed that and everything was gravy.

Oh yeah and I honestly couldn't tell you how to do the caster, I just thought mine looked good and hooked it up.

Well I measured the track bar as best we could, and it looks like the axle is equal on each side. But I don't have a means to measure it exactly, so I can't be certain. I'm pretty sure it's right on though.

My lower control arms are not adjustable. Where the lower control arms mount to the front axle, they are near the bottom of each bracket.

I'm wondering if I can loosen the bolts and rotate them somehow, if that will rotate my axle.

[goodtimes]

I had very similar trouble that you describe....DW at 35+, when hitting a pothole, etc, wouldn't go away until I slowed the tires down to under 10mph. Track bar was fine (tight, centered), caster was correct (as correct as we could get it.....4.5*). Turned out to be the Toe-in was excessive. I measure 1/4" total toe in. I backed that off to 1/8" total toe, and the problem went away.

[hurley37]

ahhh Deathwobble.......isnt it great!! The caster adjustment is the cam bolt holding your front lower control arm to the axlehousing. Everytime that Ive had death wobble a littl positive caster never hurts it, but negative caster will. And definitely toe adjustment will cause it. Ive gotten an alignment and had death wobble occur after because of them changing the caster and toe, when I asked for a toe only adjustment. Did you receive any alignment specs when you purchased your 4.5" springs? If not I would definitely call Rubicon Express and ask them to tell you what they are over the phone and also mail you a copy. Im sure your aware that you can not have the jeep aligned to factory specs with the lift. Goood Luck!!!!

[Chris_L]

To properly adjust your trackbar, take a 3-4 FOOT TWO BY FOUR AND HOLD IT AGAINST THE TIRE VERTICALY. Measure from the outside of the tire to the inside of the shock tower on both sides. Adjust if needed.

[flywaterguide]

I've talked to Rubicon Express and to Full Traction. I'm going to take it in to a place here that works on lifted Jeeps. Hopefully they'll be able to find out what's wrong and what it'll take to fix it.

keep your fingers crossed and thank!

Best,

FG

[mrblaine]

I've talked to Rubicon Express and to Full Traction. I'm going to take it in to a place here that works on lifted Jeeps. Hopefully they'll be able to find out what's wrong and what it'll take to fix it.

keep your fingers crossed and thank!

Best,

FG

Any time you have death wobble, you need to start with basics. Do not pass GO, do not collect 200 dollars. Period.

First- Have someone sit in the driver's seat. Have them rapidly, repeatedly, and consistently move the steering wheel back and forth about 4-6 inches either side of neutral for a total travel of the hand equal to about 8-12".

You stick your head under the front of your jeep and make sure that there is no play in any joint. Trackbar is especially bad about causing this.

Check upper and lower balljoints. Look at the relationship between the rim and the dust shield. Is it changing as the steering cycles?

Using your thumb and forefinger, put one on each side of the steering joints (tre's) and feel for unecessary play.

Put a finger on the side of the steering box and another on the sector shaft. Feel any play there? (about a sixteenth is normal)

Look at the juncture of the steering box and where it mounts to the frame. Is anything moving that shouldn't be?

When you are all done make certain your tires are spinning true and they are balanced.

95 percent of the time, you will find the cause of your death wobble in what I've listed above.

[sarah]

95 percent of the time, you will find the cause of your death wobble in what I've listed above.

I do believe it worked for my Jeep!

[flywaterguide]

Any time you have death wobble, you need to start with basics. Do not pass GO, do not collect 200 dollars. Period.

First- Have someone sit in the driver's seat. Have them rapidly, repeatedly, and consistently move the steering wheel back and forth about 4-6 inches either side of neutral for a total travel of the hand equal to about 8-12".

You stick your head under the front of your jeep and make sure that there is no play in any joint. Trackbar is especially bad about causing this.

Check upper and lower balljoints. Look at the relationship between the rim and the dust shield. Is it changing as the steering cycles?

Using your thumb and forefinger, put one on each side of the steering joints (tre's) and feel for unecessary play.

Put a finger on the side of the steering box and another on the sector shaft. Feel any play there? (about a sixteenth is normal)

Look at the juncture of the steering box and where it mounts to the frame. Is anything moving that shouldn't be?

When you are all done make certain your tires are spinning true and they are balanced.

95 percent of the time, you will find the cause of your death wobble in what I've listed above.

Hey Mr. Blaine,

That's great advice. The guy at Rubicon Express told me to do the same exact thing, so when I get home, I'm gonna do it.

I've had it aligned and realigned. I've had the tires balanced a few times, but that may still be a problem. I know my caster is off, but within the spec range for RE.

I'll post the results.

Thanks again,

Jeff

[flywaterguide]

I do believe it worked for my Jeep!

Sarah,

What was wrong with your Jeep?

[sarah]

Sarah,

What was wrong with your Jeep?

Worn out trackbar. A new RE one is on the way, but in the meantime we have another newer stock one and it has cleaned up most of the issues. Drives like a dream compared to before!!

There may have been a couple of other issues too, but as far as I know that was the main one. Rick may have to chime in later.

[mrblaine]

Hey Mr. Blaine,

That's great advice. The guy at Rubicon Express told me to do the same exact thing, so when I get home, I'm gonna do it.

I've had it aligned and realigned. I've had the tires balanced a few times, but that may still be a problem. I know my caster is off, but within the spec range for RE.

I'll post the results.

Thanks again,

Jeff

In my experience fighting and finding D/W, alignment is very near the bottom of the list. At least in the bottom 3 percentile.

Top of the list is out of round rims that balance, but don't run true. I don't care how many times you balance an out of true rim, it's still gonna wobble.

Here's why I believe that D/W is not caused by alignment issues- I had it on my rig after setting up new steering. New whole front end, but aside from that, I set the toe-in at 0, 1/8 and 3/16's in and then the same out without changing the onset point or severity.

I cranked the caster from almost 0 to 7 degrees in 1 degree increments.

I re-balanced the tires and stood there watching for hop in the tread or rim. Nada.

The culprit? Very high dollar rod ends with high strength ratings with only 2 trips to JV on them. Because of their high misalignment, the races while strong, were not wide enough to have any durability. There was play in each one that totalled enough combined to allow death wobble.

I'd really like to see a dissection of the cause of D/W sometime. I can get my head around the mechanics, but I'd like to see it proven.

Here's my theory. A tire, as it spins, acts like a gyroscope. It wants to go straight and as you turn it, it tries to fight it. In fighting it and having another gyro on the opposite end doing the same, any looseness in the restraining links will let oscillations start that get bigger and bigger. If a tire is out or balance or rim is untrue, the oscillations will start easier and then the tire starts hopping off of the ground as well as wobbling.