Saturday, April 17, 2010

Death Wobble solved! See initial posts below. Now to figure out why components are wearing prematurely..?

I finally got it fixed. It turns out the shop I had taken my truck to replaced the initial thing that was causing the death wobble but during their diagnosis of the track bar they had to cut off one of the bolts due to rust. They replaced it with an aftermarket bolt that was grade 8.8 instead of the 10.8 OEM bolt and they left it loose!

I paid them to do the 2008 steering update with the heavier drag links, tie rods, pitman etc.. which solved the initial issue of worn tie rods (only 40k miles on them) but because that bolt they replaced was loose the death wobble was now caused by that issue.

They ended up replacing the upper and lower ball joints on both sides and it still had the wobble. They were at a loss to explain why it still had a wobble and gave me the truck back. I took it to a Dodge dealer and they found the loose bolt and replace it. voila! no death wobble! I made the first shop pay the $140.00 Dodge bill since they blundered..

Moral of the story, always check the track bar an steering damper first!

Monday, March 22, 2010

Death Wobble on 2005 Dodge Ram 2500 4x4 SRW QC SB

I have 2005 Dodge Ram 2500 4x4 Quad Cab SB Laramie, 5.9L Cummins with 84,000 miles on it.
It's completely stock except for the Rancho steering stabilizer.

I've been having the infamous Death Wobble and can't get rid of it.

It seems to happen on the flat or going uphill with either constant speed or acceleration when the left front tire hits a bridge joint or pothole. I haven't experienced it when the right tire hit a bump first..

What I've replaced and or checked this week (3/19/2010):

  • All drag links, tie rod ends and the pitman arm were replaced with the 2008 upgrade.
  • Upper and lower ball joints both sides replaced.
  • Rancho steering damper checked - good
  • Steering gear checked - good
  • Track bar bushings checked - good
  • Front Axel U Joints checked - good
  • Wheel bearings checked - good
I've spent $1844 this week on the above and it still wants to shake apart.

I'm looking for comment on other components that may be causing this issue such as:
  • Shocks
  • Caster
  • Scrub Radius
  • Tire Pressure??
Any help would be greatly appreciated.


    Mostly Linux: Dodge Ram 2500 Death Wobble Cure. Updated

    One post from John Molidor has some good insight. Mostly Linux: Dodge Ram 2500 Death Wobble Cure. Updated

    "These problems are all very serious and it is a terrible shame that Dodge has not stepped up and addressed these issues.
    Play in front end components is not the cause of these problems. It is the forces that the front end components are being exposed to.
    Wear and tear in Ball Joints and bushings is and should be expected. The fact that any marginal amount of wear results in these issues and escalates to the death wobble means that there is a serious inbalance in the forces being applied to these front end components.
    These forces are primarily the result of a balance between Caster and Scrub radius. Both these measurments are the result of the Steering Axis Inclination Angle.
    The pivot points for the spindle or the upper and lower Ball Joints are not perfectly vertical. The upper ball joint is always slightly rearward and inward of the lower Ball Joint. The amount of tilt back of this angle creates Caster and the amount of tilt inward at the top helps determine the Scrub radius.
    Caster creates a self centering force much like the front casters on a shopping cart.
    Scrub radius however is much different. Positive and negative Scrub radius results in a force that either forces the front of the wheel in or out as the vehicle travels forward. The faster you travel the higher this force is.
    Under normal driving conditions this is the force that is always pushing or pulling on your front end parts. This force is also what causes the steering wheel to be pulled put of your hand when one of your tires hits a big bump. This is usually countered with a steering stabilizer.
    Any car or truck that needs 6 degrees of caster to drive stable is probably suffering from a poor Scrub radius.
    It is very likely that a poorly engineered Scrub radius is what is causing the majority of these issues.
    Scrub radius is where that pivot point makes contact with the ground at the contact patch of your tires. It can be changed slightly by changing your static Camber or with wheel offset and changes in tire height.
    If the pivot point is at the center of your tires contact patch there will be no adverse forces applied to the front wheel. If the pivot point is inside of the center of contact area the tire will want to turn out and the opposite is true for the pivot point being outside the center, the wheel will want to turn in.
    The further off of center that this pivot point is the higher the forces that are being applied to your very expensive front end components.
    If you can minimize the Scrub radius you will minimize these forces and it will take less Caster, less steering stabilizer and you won't have to have brand new steering components to avoid the dreaded Death wobble."
    John Molidor