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Death wobble!

2K views 26 replies 15 participants last post by  JEEPDON 
#1 ·
Please help! I have a 2010 wrangler unlimited. I put a 2inch lift kit under it. I had to put adjustable upper steering arms and had the caster adjusted to +4.6 The car still goes into a death wobble. Any ideas????? It's so unsafe. Thanks
 
#2 ·
#8 ·
Service manager is FOS! DW can happen to ANY vehicle with a solid front axle!
Even a 1956 IH 2wd pickup!
 
#9 ·
Thanks for your help. I have replaced bushes, pan hard rod, upper steering amongst other things., banging my head against a brick wall dealing with fiat Chrysler group. The reason I call it a car is probably due to the fact that I live in Australia and that's what we call them
 
#10 ·
I have owned this jeep for over a year and can't wait till it's safe so I can sell it. It's the biggest lemon I have ever purchased. In a period of 12months I have had it out of the mechanics for a total of 4months. Things might be different in the u.s but in Australia they don't have a good name
 
#14 ·
What size tires do you have? Does your death wobble happen when you hit a certain speed or after you hit a bump. I just went through all this and can probably help you. Believe it or not DW is often solved by re-balancing tires. Also, put in a heavy duty dampening bar/stabilizer I don't care what other guys say about it "covering up". DW tears the hell out of your front end, the sooner you stop it the better.

Tell me this, what size tires do you have?
Does it happen at a certain speed or after hitting a bump?

PS: I love Jeeps, this might be my last though, far too many mechanical issues with them. I hope and pray that Ford will bring the Troller T4 to the US, I'll be all over it.
 
#15 ·
DW alone doesn't make it a lemon. It is an inherit issue with the suspension/steering design.

Unfortunately, it is also common for it to take an extended period of trial and error to fix it. As Old Dogger said a common cause is for the joints on the Panhard rod to wear out, sometimes because they are loosened and then not tightened properly. The biggest challenge is that the longer it persists the more joints can be damaged.

Start by getting your tires dynamically balanced so the problem doesn't get even worse. Then, the best way to troubleshoot is to systematically check every single joint on the front suspension and steering, make sure they are all torqued properly and replace all faulty ones. Planman's video and procedure is simple, fast and works.
 
#18 ·
To fix your DW, have your mechanic check these in this order
1. Track Bar bolts: check for loose bolts and/or "ovaling" out of the brackets
2. Drag Link Ends: check for any signs of irregular movement
3. Tie rod ends: same as drag link ends
4. Ball joints: with jeep off the ground, grab the top or bottom of the tire and push and pull. Any movement signifies bad ball joints. Also check for oil leaking out of them.
5. Steering Box
6. Unit Bearing
7. Check tire weight balance
Remember that steering stabilizers DO NOT fix DW
 
#21 ·
Here is an explanation that best describes 'death wobble' in as laymen's terms as I can provide;

Too much scrub radius is the biggest culprit.
Death wobble [on cars with good componentry] is caused by forces fighting each other. All it takes is a bump to start this chain reaction.
Generally, 'toe' is used to negate the effects of 'camber thrust'. Negative camber needs toe-out, positive requires toe-in.
Designers of vehicle geometry try to put the kingpin inclination close to, or slightly inside, the centerline of the tire.
Because of kingpin inclination, if there was zero caster the wheels would 'flop over' when turned either direction.
To correct this ,the manufacturers add positive caster so the outside wheel is closer to vertical during cornering [a side effect is the vehicle will 'straighten up' when the steering wheel is released].
Sharper turning circles require more caster, but manufacturers avoid this and try to keep caster to a minimum for normal turning at average speeds ['scrubbing' tires in a parking lot isn't a safety issue]
Technically, if there were NO tie-rod, increased caster would toe the front wheels inwards [due to vertical forces]. To reduce these loads, common practice is to add some scrub radius, which would toe the front wheels outwards, causing the two geometrical forces to counteract each other.
Excessive scrub radius isn't an issue in a straight line with no bumps because the drag [toe-out forces] counteract each other [it does however 'load up' componentry more].
When only one wheel hits a bump with excessive scrub radius, that particular side will suddenly toe-out snapping the steering. As no road has zero bumps, this is the norm.
Common practice is to increase positive caster with the myth that this alone increases straight line stability.
Excessive scrub radius combined with excessive positive caster in a lightweight vehicle is where the oscillations will start [all it takes is a bump for the scrub radius to start the chain reaction]
The lighter [or more raised] the vehicle, the worse it is because caster will lift the vehicle instead of forcing itself to return to a straight line position.
If the L/H wheel hits a bump, the steering will snap to the left, causing the caster on the left to try to steer to the right. These oscillations will go past the straight ahead centerline because there is excessive caster for the weight/height of the vehicle.
Oscillations of this type are always magnified along a solid axle steering suspension.
The closest thing to a 'fix' would be to reduce caster and reduce scrub radius, all other methods are patches [providing componentry is in good condition].

Hope this helps you understand this effect..

(btw-many here seem to confuse 'caster' & 'angle of attack'. Imo-the advantage of C/A drop brackets is the maintainence of C/A attack angle, not increased caster-which can conspire to magnify 'death wobble' with scrub radius changes)
 
#25 ·
Good post!

Too many owners pay absolutely zero attention to scrub radius, probably because its effects are not as directly and immediately evident as Caster angle. It is rare to see a post where Scrub Radius is even mentioned much less considered when selecting new wheels. It's all about clearance (backspacing), appearance and so-called "stance".
 
#24 · (Edited)
^^^Also make sure that you keep your Track Bar bolts torqued, to 125 lbs.!!!

Good Luck.......:thumb:
 
#27 ·
Welcome to the forum! Plastic BJ's....welcome to the world of JEEP! That's exactly why I always recommend changing them out whenever someone is modding thier front end.... If the front axle is torn apart, that is the time to change them out! Because, at some point they WILL get changed out!
 
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