I haven't read through the thread but have you replaced the factory stabilizer with a Bilstein stabilizer? That will make an incremental improvement. Final step (short of solving the root problem) is to install a dual stabilizer kit. Worked for me.

 

I replaced it with a Rancho as I expected to stay with their shocks (FX4 stock). After reading the negatives and finding out how short of life the originals had I went with Bilstein shocks instead (hind sight 20/20).

Why should we have to add a dual stabilizer to a truck that didn't need (or come with) one 10k miles ago???

 

I went down this road trying to find the "root" cause. Never did. Everything tested and spec'd out "fine". In the end, I have replaced the factory stabilizer with a Bilstein and installed a dual monotube Rancho stabilizer kit. The wobble started to return last fall so I replaced the second set of Rancho shocks with Bilsteins. Wobble is kept at bay for now. I can't say I notice much difference between Rancho shocks and the new Bilsteins but I suspect the Bilsteins will last longer. In another 30,000 miles we'll know for sure.

I don't know why our trucks wobble while most don't. It's my only real beef with this otherwise problem-free truck.

 

You're lucky that this has been the case.

I'm holding off on dual stabilizers as I want to know if the problem is reoccurring, especially as it's still under the extended warranty coverage. I may upgrade the Rancho to the best single Bilstein though.

As I mentioned I'll be doing (or Ford Will) the sway bar bushings and links just to complete the replacement of any possible worn parts.

 

I have a 2011 F-350, and when mine does it, my front sway bar has slid to the drivers side in it's mounting rubbers. I have to take a hammer and knock it back to the middle and it goes away. I plan on replacing the tie bolts until then I just knock it back in line and it is fine. A gut at the local tire alignment shop showed me that trick.

 

do you have an idea of what they did with the camber/castor adjustment? I've seen buelletins from ford stating that reducing caster would help meanwhile everyone else says that adding caster fixes it. Im pretty desperate to get this fixed on mine. Bought the thing last week and iv already done tie rod ends/drag link with no improvement. Thankyou

 

What bulletins have you seen that say to reduce caster?! That is definitely the opposite of what would help...

Lots of things play into death wobble, worn ball joints, track rod, worn steering damper, too light of caster. You could give George at 8lug truck gear a call. They are a wealth of knowledge with this stuff.

 

It does say "reduce" as that's what they did to mine along with everything else. It still happens around 55mph every now and then. Isn't it fun wondering!

 

Generally when you put on larger tires they increase caster, so you have to reduce caster in order to compensate and get closer to OEM.

Yes, at first blush many think, the size of the tire does not matter. If you draw a circle on top of a straight line, no matter how large the circle is drawn it still touches the line in the same exact place. However tires are not round, they have a contact patch and the larger the tire the contact patch grows larger. In addition larger tires generally mean less air pressure in order to get proper wear. I found that with 12:50 x 37 x 17 BFG KM2 tires on my Jeep Rubicon I could only run about 14 lbs psi in my tires and still have a proper contact patch.

A lot of guy reverted back to non radial tires trying to kick the DW...helped, but nothing else.

The key on fixing DW is at its root cause and that is wear in the track bar. That is almost always were it begins. That said ANY component hanging under that frame can be a contributor. DW is brought on most often by a cumulative effect of worn bushings whose wear is generally initiated by the track bar and then just flows thru the rest of the components.

 

No, that is not accurate enough a blanket statement to stand. There are numerous potential causes for recursive oscillations of the steering axle and enabling factors to be addressed. Definitely a check of the track bar and is bushings is among the list of items that should be done in nailing it down, but it is a gross oversimplification and simply too often inaccurate to say that the problem starts with the track bar. In fact, it usually does not.

 

The key on fixing DW is at its root cause and that is wear in the track bar. That is almost always were it begins. That said ANY component hanging under that frame can be a contributor. DW is brought on most often by a cumulative effect of worn bushings whose wear is generally initiated by the track bar and then just flows thru the rest of the components.

 

I'm really struggling with this "increase" and "reduce" language.

From TireRack.com: "Increasing the amount of positive caster will increase steering effort and straight line tracking, as well as improve high speed stability and cornering effectiveness."

So reducing positive caster as some are saying WILL NOT help death wobble, and adding larger tires in fact reduces positive caster angle. It's also fairly well known that getting close to OEM is usually not good enough either, their specs are below. Closer to +4 or +5* seems to be the ideal caster angle.

Caster

Standard Suspension

LH: 2.7° ± 1.2°
RH: 2.7° ± 1.2°
Total/Split: 0° ± 0.55° (b)

Heavy Duty Suspension (c)

LH: 2.1° ± 1.3°
RH: 2.1° ± 1.3°
Total/Split: 0° ± 0.55° (b)

(b) Caster Total/Split = LH Caster - RH Caster

Source: Tire Tech Information - Alignment

 

Yes, that's the incorrect assertion I was referring to.

 

I won't bother to argue with you, you are trying to argue specifics and since what ever vehicle is not sitting in my shop I am not willing to say 2 vs 4 degrees. Every vehicle is different and depends upon a myriad of factors, to much caster will generate DW just like to little will. While its found mostly on solid front axle set ups, its also found on independent front suspension (non driving) and even on the front forks of motorcycles and I have dealt with every one of those successfully.

I built a business around chasing the DW demons...speaking of which I got a John Deere and a chainsaw calling. Eric, if you get back down here in my AO we can meet over at the Country Store in Helotes (be sure to bring your Doxy) and discuss suspension architecture and its effects on DW.

 

The death wobble is a series of events that creates the perfect storm. A duel steering stabilizer can mask it at times to lower the trigger point but it is still present. From tires to everything attached to the frame needs to be scrutinized, one worn bushing is not the cause but is a link in the chain, keep looking.


My first experience was a in 1977 Chevrolet K20, although death did not occur, it wasn't a fun situation.