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Death wobble ?? Maybe

jwhit

Full Member
Joined
Mar 14, 2014
Messages
198
Ok just so all know what I have
1970 with dana30 king pins new bearings
Ect last year 4" lift with 4" drop brackets
All new bushings new heat duty adjustable
Track bar with drop bracket. New heavy adjustable
Drag link ,drop pitman arm

Problem happens randomly
And may not happen all the time
And only during braking
Front shakes like death wobble
Sometimes short and stop if you
Stand on brakes harder but now
It's getting worse still only on braking
But not every time just when you
Don't want it to like in tight traffic
Now it's just getting to where it takes longer
To come out of wobble
Any thoughts???
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,353
How are the tires?
How old?
How worn?
What type?

How were the wheel bearings adjusted when putting it back together? Could they be loose, or have you done a lot of 4wd wheel bearings and know the routine?

Drop brackets? Meaning the radius arms, or the trackbar? Or both?
You said you had a dropped pitman arm, so that's good, but you would need a dropped trackbar bracket in addition to the adjustable trackbar to keep the angles correct.
More with the trackbar, what about the trackbar's lower mount? Have you tested it for a busted weld (very common) and is the upper drop bracket (if applicable) welded on, or just bolted?

And speaking of the angles... If you have a new heavy duty tie-rod, what type is it and how was it adjusted? Are the two bars still pretty parallel?

And last, but not least, got pics?;D
Good luck. Nobody likes wobbles. Especially a good old fashioned Death Wobble!
Yours is a little different, in that it tends to come in during breaking instead of during acceleration at just the right speed, but it's still got the same characteristics.
Which is why my first questions were about the tires.

Paul
 
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jwhit

jwhit

Full Member
Joined
Mar 14, 2014
Messages
198
wobble

How are the tires?
How old? 1 year around 1000 miles
How worn? none
What type? general grabbers

How were the wheel bearings adjusted when putting it back together? Could they be loose, or have you done a lot of 4wd wheel bearings and know the routine?

done bearings for years i set them by feel ,they are good

Drop brackets? Meaning the radius arms, or the trackbar? Or both?

4" radius arm brackets from wh and track bar drop bracket from duffs both are welded

You said you had a dropped pitman arm, so that's good, but you would need a dropped trackbar bracket in addition to the adjustable trackbar to keep the angles correct.
More with the trackbar, what about the trackbar's lower mount? Have you tested it for a busted weld (very common) and is the upper drop bracket (if applicable) welded on, or just bolted?

lower track bar mount looks solid no signs of cracks ect it tight as tick


And speaking of the angles... If you have a new heavy duty tie-rod, what type is it and how was it adjusted? Are the two bars still pretty parallel?

drag link that goes from tie rods to pitman arm came from bronco grave yard
its heavy version thats adjustable like standard tie rods just beefy
bars look like good angles to me i take pics tonight

And last, but not least, got pics?;D
Good luck. Nobody likes wobbles. Especially a good old fashioned Death Wobble!
Yours is a little different, in that it tends to come in during breaking instead of during acceleration at just the right speed, but it's still got the same characteristics.
Which is why my first questions were about the tires.

Paul


Paul[/QUOTE]


How are the tires?
How old? 1 year around 1000 miles
How worn? none
What type? general grabbers

How were the wheel bearings adjusted when putting it back together? Could they be loose, or have you done a lot of 4wd wheel bearings and know the routine?

done bearings for years i set them by feel ,they are good

Drop brackets? Meaning the radius arms, or the trackbar? Or both?

4" radius arm brackets from wh and track bar drop bracket from duffs both are welded

You said you had a dropped pitman arm, so that's good, but you would need a dropped trackbar bracket in addition to the adjustable trackbar to keep the angles correct.
More with the trackbar, what about the trackbar's lower mount? Have you tested it for a busted weld (very common) and is the upper drop bracket (if applicable) welded on, or just bolted?

lower track bar mount looks solid no signs of cracks ect it tight as tick


And speaking of the angles... If you have a new heavy duty tie-rod, what type is it and how was it adjusted? Are the two bars still pretty parallel?

drag link that goes from tie rods to pitman arm came from bronco grave yard
its heavy version thats adjustable like standard tie rods just beefy
bars look like good angles to me i take pics tonight

And last, but not least, got pics?;D
Good luck. Nobody likes wobbles. Especially a good old fashioned Death Wobble!
Yours is a little different, in that it tends to come in during breaking instead of during acceleration at just the right speed, but it's still got the same characteristics.
Which is why my first questions were about the tires.
 
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jwhit

jwhit

Full Member
Joined
Mar 14, 2014
Messages
198
20180720_195927.jpg

20180720_195950.jpg
how are the tires?
How old?
How worn?
What type?

How were the wheel bearings adjusted when putting it back together? Could they be loose, or have you done a lot of 4wd wheel bearings and know the routine?

Drop brackets? Meaning the radius arms, or the trackbar? Or both?
You said you had a dropped pitman arm, so that's good, but you would need a dropped trackbar bracket in addition to the adjustable trackbar to keep the angles correct.
More with the trackbar, what about the trackbar's lower mount? Have you tested it for a busted weld (very common) and is the upper drop bracket (if applicable) welded on, or just bolted?

And speaking of the angles... If you have a new heavy duty tie-rod, what type is it and how was it adjusted? Are the two bars still pretty parallel?

And last, but not least, got pics?;d
good luck. Nobody likes wobbles. Especially a good old fashioned death wobble!
Yours is a little different, in that it tends to come in during breaking instead of during acceleration at just the right speed, but it's still got the same characteristics.
Which is why my first questions were about the tires.

Paul
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,353
Looks pretty much like the normal curve that some of them have.
The lower dust boot does look to have seen better days though!

Can't see the overall angles of the two bars with the pic not showing the whole width, but from the visible portion things look pretty parallel. And at a reasonably shallow angle as well.

At this point, if you don't see anything obvious you can change, I recommend rotating the tires front to back (and vice versa obviously!) just to see if the manners change.

Paul
 
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jwhit

jwhit

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Mar 14, 2014
Messages
198
Rotating tires took it away for
Now it seems
You think rebalancing tires
Is next move?
 

DirtDonk

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Messages
47,353
Cool. Glad it's at least "under management" for the moment.
Certainly I would think it's worth checking, and if needed, re-balancing them. At this point anyway, at least the two tires that are now on the back axle.

Paul
 
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jwhit

jwhit

Full Member
Joined
Mar 14, 2014
Messages
198
Spoke to soon
Got wobble 2 times today
Only during braking
There one road that has a bump/dip
Before stop sign and I can make in go into
Wobble everyone there
 

DirtDonk

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47,353
Well bummer in the summer.
Even though I'm still on the side of the tires being the main culprit, might as well do "the test" on the steering setup just to make sure nothing is contributing to excess looseness.
Things like the trackbar lower mount (or even the upper) being loose or wobbled out, just can't be seen by the naked eye without some help. Help that a crowbar or strong hands just can't do.

I'm sure you've seen the test described where a helper is at the wheel and you're under the truck watching things?
If not, let us know and we can run down the full detailed description.

With this test you can see cracked frames, ovaled out upper bolt holes, cracked welds and loose components that don't show up any other way.

Paul
 
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jwhit

jwhit

Full Member
Joined
Mar 14, 2014
Messages
198
went thru whole front end check again sunday all is tight and no signs of any movement
did make one change i was running 25psi on tires changed to 35psi and that seemed
to reduce it that makes any since ? i think i will take truck to 4x4 truck center in next few weeks and get tires balanced and see what they see if anything
thanks
 

DirtDonk

Contributor
Bronco Guru
Joined
Nov 3, 2003
Messages
47,353
Changing the air pressure was a good call. You never know but that might help.
What is the max pressure of the tires? Maybe play with pressures some more (if there's room) to see what, if anything, that does.

I hope the balancing takes care of it, but normally when it graduates to a full wobble like you've been experiencing, it's not a balance or tread wear issue as much as it is tire defects or damage.
While it can actually be started by extremely odd wearing mud tire treads, it's usually an internal belt separation or something along those lines.
The "separated belt" is a sort of catch-all phrase for anything that is going on within the carcass of the tire itself. Some tires can take a licking and keep on ticking, while others can literally develop a death wobble after hitting a curb going into the Taco Bell driveway.
In fact, I've seen the Taco Bell Syndrome twice now. Both right front tires, both different vehicles (1EB and 1 Jeep) and both a result of Taco Bell runs.

You could hope for the best and before you have them balanced try rotating just one tire front to back (leaving one side the same), or even crossing one tire over to the opposite corner. But it sounds so far like you have at least two tires creating the drama. In those cases it's often hard to determine which tire(s) it might be.

I don't remember if you said, but the size of the tires and the offset of the wheels can have a pretty large effect on this too. If a tire has only a slight defect and is on narrower wheels with near-stock offset, you may never even feel it. But on a larger, heavier tire on a wide wheel with some extra negative offset (deeper dish, sticking out farther) the added leverage the tires and wheels have on the steering system can take it over the edge.
Can make a big difference, that leverage factor.

Good luck.

Paul
 

Boss Hugg

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Jun 8, 2010
Messages
2,140
What about the toe-in? Have you checked that? When I did my one ton TRE swap, I mismeasured and got some kinda wicked DW such that I couldn't get over 20MPH and found out later that I had 1" of toe-in on 33s. Lined it up with a touch of toe-in and it was good to go.
 

DirtDonk

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Excellent call. Definitely check all your stuff's settings if you have not already.

Paul
 
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jwhit

jwhit

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Joined
Mar 14, 2014
Messages
198
i have 33x12.50 on 10" wheels that stick out so i have alot stack against me
toe in is close to 1/8 -3/16
 
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