“Death
Wobble”©
By Jerry
Smith
HappyTrails4WD.com
The dreaded “Death Wobble”. If you have ever
experienced one, we don’t have to tell you it’s one of the scariest experiences
you’ll ever have. If you’re still a Death Wobble “virgin”, count your
lucky stars!
What Is A Death Wobble?
You are driving down a street or even out on the
open highway cruising along like usual. Your speed could be anywhere
between 30 and 85 mph. (More
often than not, it will happen around 35 to 50 MPH).
It could have been something as simple as where the
pavement changes as you cross a bridge approach or departure. Nothing
that looks sinister. Manhole covers are often the triggers.
From out of nowhere, your steering wheel begins
shaking violently back and forth so hard you can’t hold it still no matter how
hard you try. You cannot turn. The front of the vehicle feels like
it will shake apart any second.
Your only recourse is to slow down… as fast as
possible! That by the way, is the only known “safe” way to stop a Death
Wobble. We have read of people being able to “drive through it”, but
there’s never been any confirmation of that.
This phenomenon will catch you off guard. If
you are lucky, the first Death Wobble will be of the “light-duty” kind.
Consider this to be a warning of bad things to come if you don’t get it
repaired NOW!!
Any shimmy that starts all of the sudden… from no
shimmy to any shimmy, take it seriously. Once in a while you will receive
this little warning if you are lucky. Most of us don’t get a
warning. We go from normal to totally out of control in a microsecond.
That’s the way a Death Wobble works.
What
causes a Death Wobble?
** The experiences talked of here are
mostly related to Jeep Wranglers. Other experiences may vary, though not
by much**
That question causes “fear” in even the best of
auto repair shops. Most shops won’t know. The vast majorities
of them are not experienced with a Death Wobble and will have a devil of a time
repairing it.
Even a shop full of experienced technicians will
often have their hands full. This is not an “easy fix” very often.
As a consumer with Death Wobble, you will be convinced the shop is incompetent
before it is over. You may be right in this particular instance.
But before you decide, give them a lot of rope to hang themselves. They
may be very competent in most repairs, just not Death Wobble.
Most shops will have “some ideas” of what to
do. Others will just be experimenting. One thing you may want to
ask is “have you repaired any other Wranglers with Death Wobble?”
That is about the only way you will know if they are “experimenting” on yours.
Finding a shop that specializes in suspension and
alignments would be your best choice. They will need skills in those
areas well above the average.
When looking for a shop, if the first thing they
ask is when you had your tires balanced, just turn around and walk away.
Unless your tires were just installed, that won’t have anything to do with your
problem.
Imbalanced or cupped tires can be the pressure on
the trigger that starts a Death Wobble, but they are NOT
the cause. **(Read that about three
times)**
If your steering and suspension
components are all in good working condition, tires…
no matter what their condition, cannot cause Death Wobble!
A Death Wobble is seldom a “this is your problem”
type of repair. It won’t be that simple. The exception will be if
your track bar end on the frame side is really worn. That is usually the
first place to look.
The vast majority of the time, it will be a
combination of several slightly worn parts adding together to cause the entire
problem.
Those parts will include things like the ball
joints, tie rod ends, drag link ends, the trackbar ends, control arm ends, and
occasionally the need for an alignment and/or toe adjustment to be sure the
other items are working properly.
Only if the Death Wobble was one of the light duty
“warning” types will the alignment help. It may “hide” the wobble for a
while, but it will just be temporary.
One “trick” that will sometimes “mask” the problem
will be to either add or replace the steering
damper. This will not
cure the problem… just hide it temporarily if at all.
Lifted vehicles are maybe slightly more prone to
the Death Wobble. The reason for this is the change in all the angles of
your steering and suspension. Most will have a much more acute angle than stock parts would have.
If you have just recently lifted your rig, an
alignment should have been done. If not, when they do it, ask them to
make double sure the ball joints and all the steering ends are in very good
condition, not “just OK”. Small wear in each when added
together make for a lot of wear as far as a suspension goes.
Be prepared to have several new parts
installed. The first will probably be the track bar ends. (This will
require a new track bar in most cases) Next will likely be the ball joints and
then the steering linkage ends. After that, the control arm ends.
This is by no means an “always” order of things, but experience with several of
these has shown this to be “normal” if there is such a thing.
How to properly
check your steering
The following procedure is the best way to begin
the inspection of your steering. Most well trained technicians will know
how to check ball joints for wear, but the following may be new to most of
them.
Have someone inside the Jeep rock the steering
wheel back and forth enough to make the steering move the tires slightly.
This will load and unload the steering components.
(BEFORE DOING THE FOLLOWING, MAKE SURE YOUR FINGERS ARE NOT GOING TO BE PINCHED OR CUT).
(BEFORE DOING THE FOLLOWING, MAKE SURE YOUR FINGERS ARE NOT GOING TO BE PINCHED OR CUT).
Both visual and touch or “feel” inspections should
be done to each joint (tie rod ends, drag link ends, track bar ends, ball
joints, and the control arm ends… both upper and lower). Sometimes you
can “feel” what you can’t see. Be very critical of any movement caused by
wear.
When inspecting the track bar, there are some
special things to look for. First, take a wrench and check the bolt on the
axle end mount for tightness. If it is even a little bit loose, it is a
very good idea to remove it and check the bolt holes in the mount for
elongation. This
is normally hidden from view and is easily overlooked.
You can also loosen the nut and watch the bolt for
lateral movement as the pressure changes from one direction to the other as
someone violently moves the bumper up and down to see if it moves or the
steering is rocked side to side.
A better way to check for this is to observe the
bolt as someone moves the steering wheel back and forth loading and unloading
the pressure on the track bar mount bolt. Movement here is a prime source
of the Death Wobble.
Next, check the frame end of the track bar.
This one is often best done by feel as you can often feel movement you cannot
see. Just be careful not to get your fingers
pinched.
Often, the tapered stud (on the TJ) will move in
the bore of the hanging tower as well as the ball joint can be worn. More
often it is the stud in the bore moving.
On the TJ)
you will want to check the torque on the nut with the cotter pin. This is a taper fit stud that loosens from
use. The stud stretches and then the
tapered bore begins to wallow out.
You’ll need to remove the cotter pin and torque the nut to specs. Don’t forget the cotter pin when done.
Watch for twisting in the main frame while checking
this as well. The leverage on the tower can overcome the frame and weaken
it over time.
Next check the steering gear for movement on the frame
and in the gearbox. Once in a while a steering box will loosen on the
frame and move.
Check the control arm ends for movement. Here
again, like the axle end on the track bar, make sure the mount bolt holes are
not elongated as well as checking for wear in the bushings. This will
require loosening the nut(s) on the control arms as a minimum. You may want to remove the bolt to check the
bore in the mounts for being tight and round… not elongated.
Note: If you
do loosen the control arm nut and/or remove the bolt, put the full weight of
the vehicle on the suspension BEFORE torqueing the nuts. Otherwise the bushings will be twisted out of
shape when the load is reapplied and premature wear will occur.
Trying to move the control arm with a pry bar between
the mount and the control arm will usually show wear if there is any.
Make sure the wheel bearings have the proper
preload and then lift the front tires off the ground enough to be able to
rotate the tire and wheel. Check the wheels for run-out (make sure they
aren’t bent). You might want to check
the brake rotors while doing this too.
Look for cupping or
other abnormal wear patterns in the tire tread. “Reading” tire wear
patterns can tell you a lot about a suspension and alignment with a little experience.
A good alignment tech can do this.
While the tires are up is a good time to check the
ball joints for vertical wear. There should be very little or no vertical
movement in the ball joint.
This is a lot to check for, but if you don’t,
expect to repeat it sooner than later.
When replacing any parts, especially if you’re Jeep
is lifted, if you can afford them, upgrade to the most heavy duty and adjustable you can
find. The best ball joints are made with an adjustable “eccentric”
feature that allows you to adjust the camber.
The ability to adjust everything is a great benefit to “dialing in” your
steering to make your rig drive like a new one or even better.
While doing your road
tests it is a very good idea to remove or at least disconnect the Steering
Stabilizer (damper). The SS will often mask your true problem and make
recreating a Death Wobble harder.
You want to duplicate the problem, not cover it up
until you’re out driving along and it surprises you in a bad way.
You may be warned ahead of time, unless you have
all of these items replaced all up front, there is a reasonable chance you will
get your vehicle out of the shop “repaired and ready to go”, and the problem
will persist. Things will go well for a while and all of a sudden, it will
be back!
If a technician is really good, they may know of a
particular street where they can “make it happen” more often than not.
(Very, very few will have this much experience) But there is no guarantee
about this. You normally can’t just go out and create a Death Wobble at
will unless it is a severe problem.
In Grand Junction, I know of such a stretch of road
where I have experienced the Death Wobble many times. (They’re still not
fun). With that kind of background, I can tell pretty much when a vehicle
is really “repaired”, but I still will not guarantee that until most or all
joints are replaced.
OK.
We’ve replaced all suspect parts… what’s next?
It’s time to go to the alignment shop.
Here is something not many know about lifted Jeeps that can
make a big difference in how your Jeep will perform.
As you lift a Jeep, the angles on the steering and
suspension change. This is seldom good. One trick that has been
learned over time is to adjust the caster a little toward the negative as the
lift increases.
For instance, a Jeep with a 4” lift should have the
caster at +3 °, + or - 1°. (that is: +3 degrees – Plus or Minus 1
degree). The alignment tech may want to set it at +7° because the specs show
that is where it should be. That is true
for a stock height suspension.
A lifted
suspension is not stock… so you may get some argument from some alignment
shops. It’s up to YOU to educate them or
take it to another shop. This may
require adjustable control arms… but they are a must.
Doing this will also
take vibration out of your front driveline when done properly.
For a little more proof of this and a very good
education in aligning a Jeep, go to: http://www.teraflex.biz/news/cat/teraflex-video/post/teraflex-jeep-tj-alignment-training-part-1/
where you will see a three part video of a Jeep with an upper end suspension
being aligned. This suspension won’t be exactly like yours, but the
basics are still the same. And who would know how to properly set up a
suspension than the manufacturer of one of the premier Jeep suspensions?
Trust me; the time spent watching this will be rewarded.
I hope you never have to live through this Death
Wobble problem, but if you begin lifting a rig, don’t be surprised if Death
Wobble rears its ugly head after you get some miles on. Keeping a good
alignment will help… for a while. But when it is time, the only help for
Death Wobble is proper repair.
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