Jump to content

jeep comanche death wobble please help


Recommended Posts

So I just got my 6 inch lift put on my 1990 Jeep comanche and got the alignment done and tires balanced, my last step is too put my 33's on. But now I can't drive over 55 without hitting a bump and the whole front end starts shaking violently.

Everything on the front end is brand new the track bar the center link the tie rod the ball joints and the steering stabilizer.and it still shakes any ideas?

Link to comment
Share on other sites

Best write-up I've ever seen on DW:

 

 

 

 

 

My understanding of “death wobble” is this. Somewhere in the vehicle, one or more components is worn beyond tolerances, and when oscillation initiates from a suspension “traumatic” event (hitting a bump or a pothole) or also when a vibration reaches a certain point and harmonic at a certain speed, it causes theother components to react. This is called the “multiplier effect”, where one component affects one or more other components as the event travels through the front end of the vehicle.

 

 

 

Death wobble is not uncommon with the XJ. It is even more common with a lifted XJ. Finding the worn component or components is not always easy. It can sometimes be downright difficult. Sometimes it’s obvious. other times everything appears to be okay when you perform an inspection on a hoist, but getting the vehicle up in the air and going over everything with a fine tough comb is always a good first step. It is very helpful if you know exactly how to perform a comprehensive inspection of every single front end part, looking for abnormal wear and or play in that hardware. If you do not know how to do this type of inspection, pay an experienced professional to do it. Be sure to ask them if they are familiar with “death wobble”, as not all technicians are versed in this…..

 

 

 

Check out the below link if you would like some extensive reading on “death wobble” causes and cures. From my research, Kevin (the author of this tutorial) is possibly the best in the business with tracking down root cause of death wobble. He does offer hardware for sale that can help resolve death wobble, but even if you don’t buy any parts from him, you can still get some excellent ideas on what to look at in resolving your death wobble.

 

 

 

http://www.kevinsoffroad.com/how-to-fix ... th-wobble/

 

 

 

Possible causes of death wobble are listed below. Isolating death wobble is a process of elimination and the root cause is not always obvious and it can often be caused by a combination of things! From my personal experience, I would first concentrate on the track bar and the control arms and associated bushings.

 

--------------------------------------------------------

 

-Front tires out of balance (try swapping fronts to rear and see if symptoms change)

 

-Tire pressure. Don’t laugh. It’s not a root cause but can exaggerate the problem. Experiment with lower tire pressure to see if it helps

 

-Improper lug nut torque on wheels

-Front alignment out of spec

-Loose track bar

-Worn track bar bushings

-Worn track bar (check for play!!)

-Bad control arms and associated bushings

-Worn/damaged steering stabilizer (not generally a cause in and by itself)

-Worn/damaged shocks

-Worn/damaged tie rod end

-Bad U Joint

-Bad ball joint

-Loose frame mount

-Steering box loose

-Bad front hub assembly

 

 

 

 

 

Tom Walker

Link to comment
Share on other sites

So I just got my 6 inch lift put on my 1990 Jeep comanche and got the alignment done and tires balanced, my last step is too put my 33's on. But now I can't drive over 55 without hitting a bump and the whole front end starts shaking violently.

Everything on the front end is brand new the track bar the center link the tie rod the ball joints and the steering stabilizer.and it still shakes any ideas?

A 6" lift and you had an alignment done? What specs was it aligned to? Did you get a printout of the final settings? One of the keys to avoiding death wobble is to have sufficient caster angle, and with a 6" lift if you have stock control arms, or even stock uppers and adjustable lowers, it's unlikely the shop could adjust the caster to within spec -- and with a lift and big tires, "within spec" may not be enough, you probably really need to be at the maximum.

Link to comment
Share on other sites

Who did the alignment? if you did it yourself, did you adjust the caster? If you didnt do it yourself, go to whoever did it and ask them if they did. If you don't have enough positive caster, it will make it MUCH easier for something to set DW off. When I added the 4wd front axle to mine, I originally just set the toe and went, but got DW at certain times. I put it back on the rack to to do a caster swing to check that, and I was at about 4 degrees. Spec is 6.5 to 7.5 degrees. The adjustment on mine was at the rear bolt of the lower control arms. I was able to adjust it to 6 degrees and no farther, so I went with it and havent had DW since. I know this is only one factor in a long list of things, but It is one that you need to make sure is right before throwing any more parts at it. If you can't get a proper caster reading with this adjustment, then I highly suggest a new set of adjustable control arms, so you can get these readings where they need to be. That and maybe some control arm drop brackets. At 6 inches of lift the control arm angles will be high and the drop brackets will bring that angle back closer to stock for better angles and better ride quality. Some people hate the idea of drop brackets, but if you arent doing heavy wheeling, they may be just what you need. Good luck.

Link to comment
Share on other sites

Putting in new steering stabilizers are just band-aiding the problem, other parts are worn or loose as stated above!

Worn parts do NOT cause death wobble. As I have stated before, I have experienced true death wobble twice. Once was in the '88 MJ -- AFTER I had removed the lift and replaced just about every replaceable part in the front suspension. The issue was tire balance, nothing more. Rotated the tires and the problem never came back.

 

The other time was in my then-new 1999 Grand Cherokee WJ, when it was maybe six months old and had well under 10,000 miles on it. All stock, had never been off-road. Death wobble kicked in at between 50 and 55 MPH when, going down a long downgrade, I touched the brakes lightly to maintain the speed limit. The rotors were warped, and that set it off. But -- the rotors were warped before the incident (I was 250 miles from home at the time) and the rotors stayed warped for weeks afterward. But that was the only time death wobble occurred.

Link to comment
Share on other sites

I've had death wobble twice myself.

Once from a bad tire(tread separation).

And once from a worn out track bar bushing.

My son's XJ gets DW from completely worn out front suspension. No lift and new,true and balanced 215/75-15 tires.

 

Its the bump you hit that causes the DW

Link to comment
Share on other sites

  • 1 month later...
  • 4 years later...

 

Putting in new steering stabilizers are just band-aiding the problem, other parts are worn or loose as stated above!

Worn parts do NOT cause death wobble. As I have stated before, I have experienced true death wobble twice. Once was in the '88 MJ -- AFTER I had removed the lift and replaced just about every replaceable part in the front suspension. The issue was tire balance, nothing more. Rotated the tires and the problem never came back.

 

The other time was in my then-new 1999 Grand Cherokee WJ, when it was maybe six months old and had well under 10,000 miles on it. All stock, had never been off-road. Death wobble kicked in at between 50 and 55 MPH when, going down a long downgrade, I touched the brakes lightly to maintain the speed limit. The rotors were warped, and that set it off. But -- the rotors were warped before the incident (I was 250 miles from home at the time) and the rotors stayed warped for weeks afterward. But that was the only time death wobble occurred.

 

This is not an accurate statement. As the list shows above "death wobble" can have many origins beyond unbalanced tires. Tires are were I always start and work backwards....but i myself have had death wobble that was the result of worn parts (different in all cases) that was resolved by replacing (or removing repairing and re-installing) the worn part. And is some cases it might be more than one part that needs to be looked at..........and if adding a stabilizer solves it.....start working backward from there....if the tuck is set up right you can run without the stabilizer and have no problems.

Use the list above as a guideline and eliminate all one at a time until you find the cause.   :thumbsup:   . :MJ 1: .

Link to comment
Share on other sites

 

Steering stabilizers mask the problem; don't fix the problem.

 

Correct.

 

I would argue that the statement is mostly incorrect.

In a system where harmonic oscillation is a problem, adding a damper (like the steering stabilizer) is a perfectly sound engineering solution. That said, unless the factory stabilizer is worn out, replacing it won't do much, and if the vibration causing the death wobble is severe enough to cause it with a perfectly functioning damper, then yes, there's something else that needs addressed. No tire is going to remain perfectly balanced (flat spots from sitting for short periods, uneven wear from hitting cracks in the road, etc) so there's always going to be some vibration in the system which the steering stabilizer will successfully dampen and prevent from causing problems, unless the steering stabilizer is worn out of course.

 

But this is an old thread about a very controversial issue, so I'm not hugely interested in arguing about it. There are so many potential causes of the vibration that could trigger death wobble that there are so many possible solutions. Be it tire balance, worn out ball joints, bad wheel bearings, failing suspension bushings, worn out/bent steering components or suspension links... no one solution is going to be a guaranteed fix for someone else's problem.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...