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Unread 03-20-2014, 08:38 AM   #16
Pigdog11
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Enough with the bickering, I ordered the KOR bushings last night, time will tell I guess.

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Unread 03-20-2014, 08:56 AM   #17
MuddyWJ
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Quote:
Originally Posted by Pigdog11 View Post
Enough with the bickering, I ordered the KOR bushings last night, time will tell I guess.
You will be very happy with these bushings. Just make sure when installing them to use plenty of mineral or silicone based grease. Petroleum based will deteriorate the poly.
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Unread 04-09-2014, 06:58 PM   #18
sparky952
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Quote:
Originally Posted by TURNER76
You are contradicting yourself.You said It yourself there Is no cure all.Then you say there Is cure.You also say this can happen with any solid axle vehicle.Name one that has a rep like these jeeps have for death wobble.It Is known as the Infamous jeep death wobble after all. You can replace all the parts you want and yes It will help but It will not give a 100% chance of no death wobble Is all Im sayen.
Seriously. It's not a jeep thing. We have a Ford at work that has death wobble. It's a 4x4 straight axle in front. WORN SUSPENSION PARTS AND ALIGNMENT "cured" this. It's strange that we use the word 'cure'. It's a symptom indicating a problem that needs to be fixed. By the way I feel you pain. Both myself an a friend are both dealing with DW. It's all about fixing worn parts am correcting the geometry that was changed due to lifting it.

I forgot to ask, are you an engineer? What exactly is the flaw you are 100% certain of? I'm curious. Most of the people I know that have lifted vehicles are not engineers. We are all very capable mechanics, and we learn as we go. However, Mopar spent millions to design these things and we spend $100's to change it.
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Unread 04-09-2014, 08:30 PM   #19
Mp5ben
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Like everyone else has said, not a design flaw. Go into alignment shops, 4x4 shops, parts stores and ask about death wobble. Its not just a Jeep thing, it can plague anything with a solid front axle. I've gone through all my steering components and have narrowed it down to my caster angles.

To OP, get an alignment sheet readout. I just have to find a shop that will actually align my Jeep with adjustable control arms without wanting an extra $200...
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Unread 04-09-2014, 09:52 PM   #20
mtnhigh
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You can't really call it a design flaw of "jeep". They designed the vehicle to run/perform at stock specs. You choose to lift your vehicle, changing the original geometry.
Not saying a stock vehicle can't get death wobble, but as long as the suspension and steering components are in good shape, a stock vehicle is not likely to exhibit the same symptoms.
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Unread 04-18-2014, 10:29 PM   #21
tinman77
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Ah for the love! I have the JKS with hard core bushings and it definitely helped with the death wobble. However it still feels like the driver side front wheel is loose when driving down the road. Now I also have a serious bushing noise that happens all the time and you can feel every fricken bump. It only happens when the outside air temp is above 45 degrees thou. It feels like something is loose all the time but I cannot figure it out, I have gone over and over the suspension and nothing is loose. I have noticed that every time I mess with the track bar Death Wobble gets better so I believe I'm heading in the correct direction. I have noticed that the jamb nut easily comes loose after a few hundred miles. Has anyone else had this same issue? Thinking may have to double nut it or even weld the jamb nut. I also noticed that the bolt holes do have some play when loose but the holes do not appear to wallowed or oval.

04 Grand Cherokee 4.7H0
4 inch RC X-treme lift
JKS Adjustable track with Hard KOR bushings
Heavy duty Ranch steering stabilizer
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Unread 04-18-2014, 11:31 PM   #22
TURNER76
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I have same problem with the jam nut,I check It all the time.Its hard to tighten while on the jeep.I am In the same boat as you as far as It feeling like something Is always loose. I have replaced everything except the axle bushings. Im gonna try some different shocks,love the way It looks but to be honest I dread driving It and that sucks after all the money I have put Into It.
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Unread 04-18-2014, 11:50 PM   #23
tinman77
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yeah I totally agree. I just climbed underneath it tonight and sure enough it was loose again. Its strange how nice it rides after I tighten the nut down and how absolutely ****ty it rides when its loose. I emailed KOR tonight to see if they have any advice. What kind of socks are you running? I have the RC 2.2's, I took the rear off a few weeks ago because I had to replace the entire rear end. The shock felt completely gone. No resistance what so ever. I have a set of pro comps with about 10k on them that I bought when I only had a 2" BB on. Im wondering if they will fit with the 4" lift.
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Unread 04-18-2014, 11:59 PM   #24
TURNER76
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I have rancho shocks In the front and monroe load adj sensa tracs In the rear,they have a coil spring around the shock and are just way to stiff. I have skyjackers on the way gonna try them.
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Unread 04-19-2014, 05:45 AM   #25
asatxj
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There are a host of DW threads on lifted and even stock solid axle vehicles, I've had it on XJ's and WJ's. It can be fixed. Proper suspension geometry is essential. Replacing worn components (bushings, TRE's. hubs etc) is part of the mix. A good TB is essential. Proper alignment etc. If you follow the directions in the "DW cure" threads you can fix it. When you lift it, you change the geometry away from it's design parameters thus issues arise. Find and solve the issues, vehicle drives as intended. Take logical steps to remedy it and you will remedy it. IF you can't fix it, sell me your jeep cheap!
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Unread 04-19-2014, 07:01 AM   #26
Darnice
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Its real simple, look at the suspension before you put on a lift. You will see the steering arm and drag link are parallel and move in the same arc plane going over bumps (thats why the pitman arm has a bend in it from the factory.

Now put on your lift, and look at the same 2 links from above. Are they still parallel? No, do they move in the same arc? no.
Why is this, well, you lowered the passanger side of the steering arm, increasing the angle across the chassis to the pitman arm. Sure you adjusted it to make it longer, but the angle stayed the same. No longer parallel with the drag link.

That being said, what happenes now when the suspension compresses? The right front wheel will turn out because the steering arm is moving in a larger arc. The drag link, pulls the left wheel along with it.
If the suspension extends, the opposite happens. pull the wheels the other way.

So what is death wobble, its when you set the suspension in motion, and it begins to occilate back and forth between the 2 above conditions.

A good track bar, well, again, if the suspension is lifted, its relationship to the above cross bars has changed and it actually causes the entire from axle to move left to right with suspension flex because its angle of arc has changed from stock.

So if you notice the stock layout, all 3 bars move in the same vertical arc plane, when you lift the jeeps, that goes away, and DW can occur.

So whats the fix, Well, a good alignment is a must and a good starting point. Adjustable control arms to get your pinion angles correct and axle caster are necessary, but even if they are perfect, it does not eliminate DW.

So to stop DW, you have to get the links drag link, steering and trac bar parallal with each other.
1. Drag link, well its your starting point as it reference never changes no matter how high the lift.
2 . Steering arm, well must be parallel with the drag link, the closer the better, can be acomplished with a drop pitman arm, or a right side high steer kit. Either is fine as long as end up parallel to the drag link
3. Track bar, well drop the frame mount so the track bar is parallel with the other two at the axle end. Adding a longer bar to reach due to the lift actuall cause DW, because the axle is forced left and right every time the suspension moves.

I talked about arc's, there are 3 in the front suspension geometry. Left wheel, right wheel, and both up and down. Change any one from stock, and DW can ensue.

Everything from the factory move in designed arc's, as close as possible to horizontal. Why you ask, well if you look at an arc, the least movement horizontally is at the 90 degree part of the arc, then more you move away from 90, the more lateral motion is introduned for every bit of vertical motion.

This is what DW is, the lateral motion of a suspension member moving in a vertical plane that is not at parallel position to all the other suspension geometry.
On big lifts, 3-4 " you will be pushing the right wheel out with the steering arm on every bump, an pulling it back on evey hole, the track bar will be pulling and pushing the axle left and right on every bump. Soon the whole thing can start to occilate and DW happens.

So the fix is not stiffer busings, or fancy track bars, or steering stabalizers, its to get all the flex of the suspension complonents as close as possible to horizontal and in parrallel with each other.

Lets talk about suspension arms, if you lift your jeep, the arms, naturally, are now aiming down from the frame to the axle. they are no longer near level. Thus the travel has changed on there arch path, when you compress the suspension, the axle moves forward, and decompress, it moves backward.
Ok, is this bad, well, yes, because the trac bar and steering arm are fixed to the frame on one end, So every time the suspension defects, the axle will be moved laterally, and the steering will move. Not good.

Is it a design flaw, ABSOLUTLY NOT, but lifting has moved the geometry out of spec, and any vehicle will DW if this happens.

This is why Chevy vans came out with drop spindles. Ever see a chevy van with lowered suspension that did not use drop spindles? DW on those can be very bad.

So to combat DW, get your links as parallel as possible to the axle. and if your lift is very high, you may have to consider moving your mounting points for the control arm either lower or further away from the axle to reduce the arch degree change with suspension movement. High angle front control arms, whe the suspension compresses, actually cause the jeep to move backward, or the axle has to accelerate forward. This creates the Harsh ride when lifted, even with soft shocks and springs. All that lateral force is transmitted throught he control arms to the frame points and puts far more stress on the bushings than stock ride height does going over rough terain.
This is why you see racing trucks, with very long control arms, massive suspension travels, but at racing speeds, the control arms are very close to horizontal.

I know thats a lot of explination, but its to show ho one small change, like a simple lift can impact so may aspects of how the suspension and axles behave in the exact same road conditions.

I should build a model out of lego, to demonstate all of the above, it really shows what your up against .
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Unread 04-19-2014, 07:16 AM   #27
jspidle
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My '96 LR disco had DW.

Darnice, that is a great explanation. :-)
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Unread 04-19-2014, 07:45 AM   #28
ezflip
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Quote:
Originally Posted by Darnice View Post
Its real simple, look at the suspension before you put on a lift. You will see the steering arm and drag link are parallel and move in the same arc plane going over bumps (thats why the pitman arm has a bend in it from the factory.

Now put on your lift, and look at the same 2 links from above. Are they still parallel? No, do they move in the same arc? no.
Why is this, well, you lowered the passanger side of the steering arm, increasing the angle across the chassis to the pitman arm. Sure you adjusted it to make it longer, but the angle stayed the same. No longer parallel with the drag link.

That being said, what happenes now when the suspension compresses? The right front wheel will turn out because the steering arm is moving in a larger arc. The drag link, pulls the left wheel along with it.
If the suspension extends, the opposite happens. pull the wheels the other way.

So what is death wobble, its when you set the suspension in motion, and it begins to occilate back and forth between the 2 above conditions.

A good track bar, well, again, if the suspension is lifted, its relationship to the above cross bars has changed and it actually causes the entire from axle to move left to right with suspension flex because its angle of arc has changed from stock.

So if you notice the stock layout, all 3 bars move in the same vertical arc plane, when you lift the jeeps, that goes away, and DW can occur.

So whats the fix, Well, a good alignment is a must and a good starting point. Adjustable control arms to get your pinion angles correct and axle caster are necessary, but even if they are perfect, it does not eliminate DW.

So to stop DW, you have to get the links drag link, steering and trac bar parallal with each other.
1. Drag link, well its your starting point as it reference never changes no matter how high the lift.
2 . Steering arm, well must be parallel with the drag link, the closer the better, can be acomplished with a drop pitman arm, or a right side high steer kit. Either is fine as long as end up parallel to the drag link
3. Track bar, well drop the frame mount so the track bar is parallel with the other two at the axle end. Adding a longer bar to reach due to the lift actuall cause DW, because the axle is forced left and right every time the suspension moves.

I talked about arc's, there are 3 in the front suspension geometry. Left wheel, right wheel, and both up and down. Change any one from stock, and DW can ensue.

Everything from the factory move in designed arc's, as close as possible to horizontal. Why you ask, well if you look at an arc, the least movement horizontally is at the 90 degree part of the arc, then more you move away from 90, the more lateral motion is introduned for every bit of vertical motion.

This is what DW is, the lateral motion of a suspension member moving in a vertical plane that is not at parallel position to all the other suspension geometry.
On big lifts, 3-4 " you will be pushing the right wheel out with the steering arm on every bump, an pulling it back on evey hole, the track bar will be pulling and pushing the axle left and right on every bump. Soon the whole thing can start to occilate and DW happens.

So the fix is not stiffer busings, or fancy track bars, or steering stabalizers, its to get all the flex of the suspension complonents as close as possible to horizontal and in parrallel with each other.

Lets talk about suspension arms, if you lift your jeep, the arms, naturally, are now aiming down from the frame to the axle. they are no longer near level. Thus the travel has changed on there arch path, when you compress the suspension, the axle moves forward, and decompress, it moves backward.
Ok, is this bad, well, yes, because the trac bar and steering arm are fixed to the frame on one end, So every time the suspension defects, the axle will be moved laterally, and the steering will move. Not good.

Is it a design flaw, ABSOLUTLY NOT, but lifting has moved the geometry out of spec, and any vehicle will DW if this happens.

This is why Chevy vans came out with drop spindles. Ever see a chevy van with lowered suspension that did not use drop spindles? DW on those can be very bad.

So to combat DW, get your links as parallel as possible to the axle. and if your lift is very high, you may have to consider moving your mounting points for the control arm either lower or further away from the axle to reduce the arch degree change with suspension movement. High angle front control arms, whe the suspension compresses, actually cause the jeep to move backward, or the axle has to accelerate forward. This creates the Harsh ride when lifted, even with soft shocks and springs. All that lateral force is transmitted throught he control arms to the frame points and puts far more stress on the bushings than stock ride height does going over rough terain.
This is why you see racing trucks, with very long control arms, massive suspension travels, but at racing speeds, the control arms are very close to horizontal.

I know thats a lot of explination, but its to show ho one small change, like a simple lift can impact so may aspects of how the suspension and axles behave in the exact same road conditions.

I should build a model out of lego, to demonstate all of the above, it really shows what your up against .
Please explain the difference between a "steering arm" and a "drag link". This post does not make any sense. The track bar and drag link must be parallel. There are no other bars in the steering that run parallel to these. By lifting a vehicle, both the body side mount and pitman arm are raised by the same amount while both axle side mounts are unchanged. Thus, unless you are using a drop bracket instead of an adjustable track bar, or a drop pitman arm instead of adjusting the drag link accordingly, the two bars remain parallel. Regardless of how small or how big of a lift you put on it. So, Im curious what this "steering arm" is? What is this "third" arm that is supposed to be parallel with the drag link?
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Unread 04-19-2014, 08:09 AM   #29
TURNER76
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Yeah that steering arm through me for a loop. I only have a 2.5. lift and I was told adj. control arms were not needed. If I was gonna do all that I would have Installed a 4 Inch lift.I have not had death wobble since I Installed new control arms and adj. track bar,my jeep just feels like It on the verge of being out of control all the time.It may be all In my head,who nos.
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Unread 04-19-2014, 08:14 AM   #30
Darnice
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Quote:
Originally Posted by ezflip View Post
Please explain the difference between a "steering arm" and a "drag link". This post does not make any sense. The track bar and drag link must be parallel. There are no other bars in the steering that run parallel to these. By lifting a vehicle, both the body side mount and pitman arm are raised by the same amount while both axle side mounts are unchanged. Thus, unless you are using a drop bracket instead of an adjustable track bar, or a drop pitman arm instead of adjusting the drag link accordingly, the two bars remain parallel. Regardless of how small or how big of a lift you put on it. So, Im curious what this "steering arm" is? What is this "third" arm that is supposed to be parallel with the drag link?
Steering arm is the adjustable arm that goes from the steering box pitman arm to the passanger side knuckle
The drag link, connects the right side knuckle to the left one.
The reason the steering arm goes all the way across the chassis to the other side, is to reduce the horizontal deflection angle whe then the suspension moves. Reduces lateral steering deflection.

I know its a lot of techinical stuff, but it all boils down to stopping the suspension, when it moves from moving in a plane that is not desirable. EG. If the suspension moves up and down, design to mitigate for and aft and lateral movement.

This is why the rear suspension does not DW, it has a fixed point of rotation in a horizontal plane. (the center ball joint) No mater how much you jack up the rear (to the limits of the ball joint) the axle will never move laterally.
Now, that being said, if you jack up the rear, and increase the suspensions angles from level, you then add for and aft axle movement, the bigger the lift, the greater the movement. Adjustable CA's can't stop that. The just fix pinion angles.
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