Death Wobble on 2001 XLT SD 4X4 7.3L PSD
 

Hello. I have a 2001 XLT SD 4X4 7.3L PSD EXT Cab and started experiencing the death wobble a few months ago. My truck is stock suspension, and no lift or additional components. First happened around 55mph when I went across a rail road track. Last most people, I thought the wheel was coming off. It stopped after I slowed down. Now it seems almost any bump starts the wobble. I read this was common on most 05-08 models, but it not just exclusive to that model, or even Ford vehicles. I have probably read about 10-15 threads to educate myself before starting the troubleshooting and will need some experienced used to chime in. My 2001 has 338K on it. Below is what I plan to check/do based off my readings. Please let me know if some of this will not apply to my truck since it is an '01 4x4 and a lot of my findings were one 05-08 and even early 90s trucks. I'm not sure if all this hardware is on my setup based on my description of my truck above or if some of this terminology/parts are the same thing.

1) Check that the tires are inflated to the spec on the door sticker
2) Replace front shocks with Rancho RS9000XL or Bilstien's
3) Torque bolts on the Trac bar, replace Trac bar bushing and trac bar ball joint
4) Replace front wheel U-Joints
5) Replace upper and lower ball joints
6) Get an aftermarket Dual Stabilizer (Is this possible if truck is not lifted?)
7) Replace Panhard bar bushing
8) Replace Shackle bushings
9) Replace I-Beam bushings
10) Replace tie rods
11) Replace idler arms
12) Replace steering box
13) Replace Steering Damper
14) Check wheel, axle, suspension, i-beam brackets for cracks / loose hardware
15) Tire balance, alignment, get camber / caster & toe-in adjustment

I know that no one has really pin pointed the issue with the death wobble, but this seams to cover most everything. Where should I start? what shouldn't I do? What doesn't apply to my truck? Please help! Thanks!

I would start at the trac bar...9 out of 10 trucks I work on it was the trac bar bushing doing the death wobble...

You don't have I beams, nor anything related to I beams like I beam bushings, so you can cross all that off your list.

You don't need to touch the "front wheel U joints" to fix your wobbling issue. If what your are describing happens to you in 2WD with the front hubs unlocked, then the joint between the inner and outer axle shafts isn't even turning, so there is no correlation.

You don't have idler arms in your application.

The Panhard bar and the Trac bar are the same thing.

New shocks won't make any difference, but a steering stabilizer might dampen the bump steer you feel when your steer tire bumps a railroad track. But you don't need a dual steering stabilizer with stock tires.

The responder before me is right... look at your track bar. Don't just check torque, check to see if the thing is still there. Ok, I'm exaggerating... the bar doesn't go MIA, but the bracket on the axle on the passenger side quite often cracks. I saw one just yesterday parked on the side of the road. The trac bar was hanging by the steering stabilizer, because the track bar bracket had broken.

Cracks come before breaks, and when the road is smooth, nothing happens, but when a bump reverberates through the chassis, the crack can grow, or become dislodged (unlocked out of the grain structure of the fissure), which would literally add an unplanned flexible joint to your steering/suspension system.

Why not make the last thing on your list (#15) the second thing on your list? Take it to a competent alignment shop, and explain your problem. When the unit is on a rack, with a powerful flash light, look carefully all around the passenger side leaf spring seat on the axle. All that bracketry and weldments should be inspected.

Bolting on new shocks might be the easiest thing to do besides checking tire pressures, but shocks will not fix, or even hide, the issue you report.

These guys got ya covered pretty good.

I'll just add that it's not hard to check the hubs and ball joints to rule them out. Jack up the front and grab the wheel at 9 and 3 0'clock and give it a manly wiggle. Do the same at 12 and 6. A 2x4 under the tire to check the 12 and 6 motion will make it easier. The tire should be solid in all directions, but loose at 12 and 6 is probably ball joints, and loose from both directions would be hubs. A helper making the motions while you observe from a comfy spot on the ground would be good.

With the truck back on the ground have your helper saw back and forth on the steering wheel, look for any unwarranted play in the linkage.

And a LOL to Y2KW57 for "I might be exaggerating"! Dude I revere your precise language and descriptors, calling the panhard MIA in this case is probably apt, not exaggeration. :-X22

A pic is worth a thousand words. Got any?

Sorry for taking so long to get back, but the track has been at a friends house until we could find a time to bring it back to my place. So here are some pictures. If I need to take more, let me know what I should go looking for.

A few more pics

Looks like you have a fluid leak.

You'll do well to clean up the underside. I use Gunk Gel for those areas, but many ways to skin that cat. Once that is done, you'll be better able to see where your problems are.

Only definite thing I see is the sway bar bushings on the axle. Probably wouldn't hurt to do the end links while your there.

Yeah I just soaked it in some gun and let it sit on all the joints for 10 minutes then hit them with a brush and water. Darkness has set now so got to wait till it dries up. Probably reapply tomorrow. The fluid is coolant. When I have the reservior tank fulled to max it seems to drop about 3/4 of a gallon. I havent tracked down the culprit yet. Truck is parked until wobble solved. To dangerous to drive right now. Wobble has gotten more frequent and happens on less aggressive bumps, but this is also first time I have driven it without the hubs locked.

If I get chance later I will post up a great discussion (which I actually learned something from) about DW. But basically do you have larger than stock tires? Regardless, start with dynamic balaning your front tires.

It almost looks like fluid coming from the front differential the way it is patterned on the knuckle? Not that this is related to your original problem, but have you checked your front diff fluid level?

On your last picture, notice the polished wear next to the bushing as if its been sliding side to side.

Not long ago I hit some bumps and thought I had the death wobble. It felt like the wheel was coming off. Pulled over and got under the truck, pulled on everything, checked the lugs, found nothing. I drove home 30mph. Ordered new wheel hubs and changed those out. few days later it happened again, bad wobble. But I noticed that time it happened when I applied the brakes. Ended up being one of my front brake calipers was sticking. Just something to check.

Mine does it without braking, and does it when going over bumps. Im pretty sure makes brakes are good right now. I'll keep it in mind though.

Yeah I see that. I don't know if my wobble has caused that but it sure seams like it could considering my seems to be side to side. What do you think would cause something like that? Obviously something lose, but what?

I lifted the wheels up off the ground to see if I could notice any play in them and the hubs appear to be find right now. While I was wobbling them, it did appear that this joint seemed a little loose. What is the torque recommendation for this and what do you call it? I'd like to check all of them on this system

Yeah this nut was almost finger tight. Am I right to call these bars in this link system the tie rods? I am going to do some searching for torqueing them.

Found this post. Hopefully this gets me going again:
https://www.ford-trucks.com/forums/1...l#post11906868

I cleaned it up pretty good and didn't notice any cracks on the top or bottom. The damper / stabilizer (same thing?) does have some dents in it though, but I dont think that is my issue right now. I'm going to retorque the tie rods first and try that.

The only one I haven't torqued is the "Steering gear sector shaft arm retaining nut" 200 Lb-Ft. It looks like I would need to take the trac bar cross member off to get to that one. Is that correct? I don't have a torque wrench that goes over 75 lbs, but I am about to order one just in case i need to work on the trac bar and for this nut also. Does anyone know what size socket the "Steering gear sector shaft arm retaining nut" is? I heard the trac bar bolts are 1 3/16" so I will likely order one of those also. Is this also correct?

I am reading that is a 1 5/16" or a 33mm will also work. Can anyone confirm that? I found a 100-600 ft lb torque wrench with a 3/4" in drive on the worlds largest auction site for $215. Does that sound like a good price?

That's about what I paid on ebay for my Snap-On 100-600 ft torque wrench.


BTW, track bar was not the problem. And my guess is that track bar is rarely the problem.

Im going to buy the wrench and sockets. I can always use them later. I hope I can track down my issue. One of my nuts on the tie rods was finger tight. Idk if that was my problem or if that happened because of the problem. I retorqued it and and checked all the other tie rod nuts to spec and the sway bar torques. Only ones I have not check are the pitman and track bar. I'm running out of things to check so hopefully that loose nut was my problem.

Here are some pics of a track bar bracket failure in a leaf sprung Super Duty:


http://i107.photobucket.com/albums/m...f/DSC04116.jpg


This is the same bracket I was pointing to with yellow arrows on the OP's post. The ripped part in the photos above and below is where it attaches to the axle, at the passenger side Ubolt, in the area above where the steering stabilizer is anchored to the axle.


http://i107.photobucket.com/albums/m...f/DSC04118.jpg


And below is where the bracket tears away from the axle. This is why I mentioned that the OP's photo isn't showing the entire bracket, because this is the area where the cracks can initiate, and should be inspected periodically on ANY 99-04 4x4 Super Duty, even if the OP's vehicle is clear. Like I said, saw one parked on the side of the road the other day, with this bracket hanging by the steering stabilizer, with the track bar still attached.


http://i107.photobucket.com/albums/m...f/DSC04120.jpg


Fortunately, the OP reports this isn't his issue. But I wouldn't go so far as to say this is "rarely" the problem. Unfortunately, it happens more often than it should.


Read the owner's story here:


Track bar bracket broke AGAIN! - Diesel Forum - TheDieselStop.com


The above 3 page thread started in 2008, but just yesterday (14 Nov 2015) the following new post was added, which reminded me of the OP's situation and reported symptoms:

I got an update. After torquing all the links on the tie rods and sway bars yesterday I took it for a spin. No wobble last night so I decided to drive it 25 miles to work. The truck was riding straight and smooth for the most part but I was scared the wabble was going to happen. I went over some speed bumps at the office and took it to the place that always guarantees a wobble. I hit the rail road tracks at about 30 mph and the wobble began. After that I started heading back to he house. The major wobble stopped, but I could still a vibration/wobble for a few miles. When I came to a redlight and applied the brakes, the wobble began violantly and the vehicle pulled to the left. I dont think it is my tire, because I rotated them recently and had the wobble before that and still have it. Always seems like its coming from the left front wheel mostly. Since its pulling to the left and seems to wobble the most on the left, today particularly after braking, perhaps I should replace the calipers, pads, and rotors on the front. It doesn't do it all the time which is whats suprising. Most of the time it brakes with out a lot of vibration and no pull, but after the violent wobble it was pulling left and wobbling during braking on the way home. Thoughts?

cpye2: Please post whether or not you have larger than stock tires and whether or not your vehicle is lifted higher than stock.

I'm stock height, my tires on the front are 235/85/16's up front.

Don't replace the calipers and rotors just yet. Just service your caliper slides and/or replace pins and grease. Check under the same conditions. It may be you have more than one issues, but this is an easy fix to start off with. While your there, check the condition of your caliper pistons and check for sticking. Also, a brake bleed to get to clear fluid will go a long way.

I bled the brake about a week ago after I put the ATF in the brake reservoir. I'm going to check out the brakes next.

Sorry, didn't correlate you being the OP on that one.

Anyway, just a thought, check the play in your hub while your at it. Roll it and listen for any bad sounds. Should be none. This can also help with understanding the problem in the brakes.

OK, I will get flamed for what I am writing below. It is considered heresy, but it is based on my extensive personal experience with DW and how I eventually cured it.

In my experience of chasing down Death Wobble, it has nothing to do with the track bar, ball joints, or caster. Yes, find and replace worn components, I am only saying some brand new Fords and Dodges with coil springs and solid axles have DW right from the factory - brand new!

I spent $3,000 with the 4x4 converter only to have the DW return in 2 years. The only thing that made it go away for a while was replacing the front tires (with half the tread left!) with new ones (Toyo AT's). I then bought a used 600lb. Snap-on torque wrench and checked my track bar bushings myself. They were fine (they were only 2 years old after all).

Don't focus on what "initiates" the DW. You can and should fix that (i.e., by replacing a warped rotor, replacing a warn bushing or ball joint, etc.). But DW is cured by damping the tie rod.

Here is the ugly truth, if your suspension has the propensity to "propagate DW" then something will initiate it, and you will be chasing down that initiating event, rather than curing the DW from propogating. (I mean it is not a single isolated bump steer that scares you correct? It is the resulting "wobble" back and forth that can kill you going downhill into a turn on an icy road with a big rig coming towards you uphill or when you are going downhill pulling a tandem one yard concrete mixer. Both of which I have experienced with DW.)

Adding the Energy Suspension track bar bushing and tightening up the steering box (both of which I did) just makes the propagation more efficient and more likely to oscillate more violently making the tie rod more efficiently transmit the bump from one wheel to the other!

So here goes, "Death Wobble" is caused by one tire (e.g., the left) hitting a bump and pushing through the tie rod up against the other tire which pushes back and continues the back and forth punching until the wheels stop rotating.

This is because a rotating tire (especially a larger than stock tire) is a rotating mass which has gyroscopic inertia which engineers may call "angular momentum." *

A rotating tire wants to spin around its horizontal axis. For example, push a spinning top off-center (i.e., off the axis of its spin) and it immediately and violently bounces back to spin on its vertical axis. So that's what must be happening with the wheels in DW. Anything can push the spinning wheel off of its horizontal axis. A bump in the road, the other tire punching the wheel through the tie rod, etc., but when your tire is bumped off its axis, that spinning tire wants to return to spinning on its horizontal axis so the tire moves to re-center itself which causes a push through the tie rod to the opposite tire which sets up the same reaction in the opposing tire and it repeats until the rotation of the wheels is stopped, killing the gyroscopic effect.

DW is a "turning" or "steering" event. That is propogated by your tie rod. That is why your steering wheel rapidly turns back and forth during DW. And that is why damping the tie rod eliminates DW.

So if you just want the DW to stop, then install dual opposing gas pressurized SHOCKS to damp the tie rod. Opposing gas pressurized shocks push against each other thereby cancelling each other out and, thus, do not put any pressure on the steering box while an opposing dual stabilizer set up (a stabilizer has resistance both pushing in and pulling out) would create tremendous resistance on the steering box (possibly causing premature wear and looseness).

Starting on page 4 here is my version of the dual opposing gas pressurized shock steering stabilizer set up:

Sportsmobileforum.com ? View topic - Quadvan Death Wobble

For you engineers, this is how bcaine on the sportsmobileforum explained DW:

"DW originates when:
1) one tire is jarred,
2) and through the tie rods this jarring is transferred to the other tire.
3) Then (not by the spring like nature of the opposing tire's sidewall) but rather by the fact that the angular momentum of the other wheel will be conserved it will resist being pushed and
4) create a sort of Third Law Force back on the first wheel, which
5) has its own angular momentum to conserve, thus SHM ensues?

If so, does a damper (really wondering if i picked the right one) dissipate some energy from the system thus bringing a more immediate end to the SHM?"

In summary, for those of you who have had DW, you wouldn't drive your truck without vertical shocks at each wheel to damp the sprung mass of the body, would you?

So why would you drive your truck without horizontal shocks connecting the tie rod to the differential to damp the horizontal gyroscopic effect of especially larger than stock tires you have put on the front of your truck?

Finally, anyone who says that dual opposing gas pressurized shocks used as a steering stabilizer are just "masking" the underlying problem is . . . in polite words: "mistaken."

For those of you who believe that . . . , please take off the vertical shocks at each of the four wheels on your truck and see if you like driving it while it bounces uncontrollably up and down without the benefit of "masking" which the vertical shocks provide by dampening the vertically sprung mass of your truck's body.

The internet is an echo chamber of misinformation. I have read lengthy posts by people who have never had Death Wobble telling other people who have it that it is their track bar or their ball joints or their caster -- even on brand new F350's!

IMHO, there should be a moratorium on people who have never had DW from suggesting to others how to fix it.

[Flame suit on, visor down...]

* My initial hypothesis that it was the "punch and rebound of an air-filled rubber tire" which causes the back and forth steering (wobble) transmitted through the tie rod is wrong.

I'll try cleaning the pins tomorrow and checking the pistons. Is there a good way to go about checking the pistons if you are alone? Also, if I find uneven wear on the pads, warped rotors and bad pistons, I have read that its almost worth buying new calipers rather than rebuilding the old ones. I found a replacement kit from PowerStop "KC1905-36" for $305 shipped. That has all the items in the picture included. Thats about what 2 Cryo Power Slot rotors alone would cost me. Would you recommend a kit like that? Seems to get good reviews.

I have that exact kit. It has served me well with one exception. Some of the pad spreader springs rub on the rotor until they are about half as thick. Didn't have this issue on OEM calipers or ART Cryo rotors I had. They are definitely a fell swoop fix for braking issues at the wheel. But understand, I had no death wobble and it was only felt during braking. I only did this because I had a frozen/sticking piston and decided to do it all at one time for a good price.

I understand. I am just trying to get my ducks in a row in case I need to buy a brake system. I remember you saying swap both calipers at one time if I have to swap one and to check for uneven pad wear. Do you have a good method I can use to press the piston out to check for rust and pits? Press the pedal with caliper off the disc? Will the piston retract after I let off the pedal? I cant find a good guide for this.

Good to have a backup plan. I count it as solid. Yes, swap both at the same time. If you replace one and the other is more worn and less effective, you'll be left with uneven braking and brake wear. Every manual, every decent shop and ever school should tell you the same. When you replace rotors, replace pads and replace both in pairs on front or rear. Similar reasons above. When I checked my pistons, I used a c-clamp and pushed one in enough to push the other out. If you press on one, the other should float out. When pressing them back in for remounting new pads, you press them together. I cut a piece of steel out to press both together. Normally the issue with these are the seals going bad and allowing contaminates into the cylinder area, which causes scoring, sticking and freezing. (That's not to say bad old and contaminated fluid and water in fluid is not a common problem that leads to brake surging and failure in calipers.) Some people rebuild calipers, but for the time required, I opted not to b/c it's my main transportation. I have heard mixed success with this and there is always the possibility that a cylinder wall will be scored beyond rebuild. They are too cheap to replace whole than rebuild in my opinion.
The pistons will not retract when you let go of the pedal. You must press them back in. Youtube it. There are bunches on videos on even our truck.

Finally, I will not disagree with the above concerning steering stabilizers. I intend on putting one on mine as well, but I do not have the DW so it's not particularly high on my list as I have must things to do at the moment.
Duel opposing would be nice, but I think a single stock style will be fine for me since I don't have the DW problem. I would not advice against a double for you though, it can only help IMHO.
But what I will say is that aggressively seeking out the contributing items to that problem is a good idea. Those items only get worse with time.
As many have said, DW can come from anything from the physics stated above to anything in the front end suspension. The more worn parts, the easier it comes to you. I say why not shore up the whole system.

Believe me, I'd like to torque every steering / suspension bolt to spec, replace all 4 shocks, add the dual stabilizer, upgrade the brake system, and replace all the bushings from the leaf springs to the sway bars. I ordered a big torque wrench and 8 impact sockets to do the pitman and trac bar if need be. Tomorrow I'm going to start the servicing of the front 2 calipers and probably do the front bearings while I'm at it. Just taking it one step at a time. I got the truck for a good price and have fixed a few things here and there. I'd say I have plenty of equity to get the suspension/braking/steering components back up to par. Truck runs and rides great. Until the wobble thing took over I'd drive this truck anywhere with 338k on it.

https://www.ford-trucks.com/forums/a...1&d=1447607441

Left Inner Tie Rod End

I had a Raybestos unit go bad in about a year, so I'd stick with a Moog or XRF.

Also a good thread for more part numbers/info/diagrams LINK

The causes, and the cure, for death wobble in a 3 link coil suspension can be different than a front leaf suspension.

If the steering dampeners were an absolute essential component for vehicle stability, then for liability reasons alone, they might be installed on all Super Duties, in fact, on all vehicles with two front steering tires, whether 2wd or 4wd. Yet, steering dampeners are not found on all vehicles as original equipment. Nor on all Super Duties.

CPYE2, from your last description of symptoms, it seems fitting to start with the left front brakes, inspecting for uneven pad wear comparing the inner and outer pad. Check for smooth operation of the slide and caliper pistons.

How long was ATF in your brake system? I wonder if there is some chemical incompatibility with an ingredient in ATF and an elastomeric in the caliper. Oils can cause some rubber to swell substantially, which could shift a seal out of place.

https://www.ford-trucks.com/forums/1...reaks-out.html