Technical Update: Fixed slow speed (5-15 mph) death wobble

I had the same problem with my A-V8. Everyone says "more caster" but that was not the case. I started with 4 degrees and ended up with about 5 to clear it up. There are many minute adjustments that can make a big difference. Personally, I can't even imagine 10 degrees of caster on a stock A front axle. I have hairpins on my axle, so adjusting caster is easy. Stock wishbones, not so easy. Bones were adjusted in the old days by bending them. Differences in camber from side to side probably doesn't help either. Back to the bending. Who knows? Not being there to see the car makes it hard to say what it really needs.

 

Steering box, rod ends, wheels and tire assys need to be new with no play and dynamic balancing of wheels and tires, then lower tire pressure so the front wheels dont hop/bounce say 26 lbs. Check the caster (6 deg.), camber ( may have to bend the axle) and toe in (1/8 in.) on an alignment machine. Truck frontend places usually have all the right equipment to set it up. JW

 

All my Experience with Caster needed
(More then 5 deg ) was for severe rake,
Also in my experience , Wheel /Rim
More then 4-1/2 wide needed to play with "Toe In " ( wide front tires)
& pay attention to pitman arm in relation to cross steer being on same plane @ ride height

 

Follow up:

I believe I fixed the problem. The tie rod and drag link ends needed to be tightened. I guess the springs have relaxed some since being installed. Front end still needs the toe in tweaked, but I'll do that this weekend.

I also noticed that the '32 pitman arm slid past the end of the splines and the factory split washer didn't go over the splines, so it allowed the pitman to walk a bit. Not sure if was part of the issue, but I machined up a washer to go over the splines and snug up against the pitman arm and split washer.

 

Good news!

 

Great news easy fix ! Happy hot Rodding

 

Thanks for reporting back. It only takes a little slop in the steering components to lead to all sorts of problems. Given that it didn't have death wobble before hopefully it is cured.

 

Good sleuthing on the pitman arm splines situation.

 

1st order of stuff like that... look for something loose. You found it... hot damn...

 

As so many HAMBers have stated, it is not a fix. It is a band-aid. Whatever the problem may be, it should be fixed. These guys utilize a damper as an improvement to their rods. Their frontends are already set up properly. Good luck with your inspection.

 

Glad to hear you located the problems. Add up a little play here and there and you have a big wobble.

 

We Funny Car/Altered drivers some time experience
""Death Wobble""
after burn out coming to a stop,
Some times all the Stars are inlined

 

i have seen this happen violently when backing up after a burnout ( neg caster going backwards)

 

Its rare , Also forward coming to stop ,
Will Black & Blue the hands
Just harmonics at the right time when it happens ,

 

My avatar will do it if backing up too quick. I've got around 7 degrees caster.

 

Nonsense.
A steering damper is not a bandaid and it isn’t a last resort.
There are well designed OEM vehicles that incorporate them from the design to the road.

 

I remember many years ago at Bonneville when Jim Davis was headed from the pits to the starting line in his then blue and white chopped coupe. He was probably doing 25-30 when the worst case of death wobble I'd ever seen started to shake the car violently. He brought it to a complete stop, resumed his trip to the starting line and proceeded to make a run down the salt. I always wondered why the car didn't do it all the time?

 

As Gary said above, a damper shouldn't be used to mask or correct an issue due to geometry or worn or loose parts. In an already properly set up system they can be used to improve the driving characteristics, but they're not a fix for a bad setup.

Hot rodder I knew had a steering damper on his straight axle car. The steering got a bit loose and bump steer got worse. He investigated and his king pins were completely worn out. The damper masked a dangerous condition.

 

So, are you suggesting that if a problem condition starts to occur with the steering, the whole steering and front suspension assembly should NOT be thoroughly checked..??? You would recommend a steering damper be fitted rather than identifying the reason the wobble has started to happen? You would just be happy that the damper "cured" the pesky little problem? Yeah right, what could possibly go wrong with that approach...........
The wobble is only the symptom. It is a real good idea to actually treat the root cause.

I will assume you have read the entire thread, so I will assume you know that the OP actually found issues that needed attention in his steering system. Imagine what could have happened if he had ignored it...???

 

Im a little confused ,not the first time!
Are posters calling / saying stabilizer as in a Shock
Connected to steer rod or cross steer
Or
A front pan Bar ?
I had a stock front end 32' with 32 wire wheels
Drove regularly No issues , Changed to 16 inch steely's Same No issues , Then drop Just axle , started experiencing D -W 3-4 times in a 10 time low speed to brake stop ,,, Testing was done @ same roads & stops ,, Check all steering from box to wheels , Still here & their on D-W,
I Installed a ""Pan Bar"" Frame to Axle No more Death
32 mention was with stock Bones ,
On Four Bar Straight Axle I always use a Pan Bar

 

I’m not arguing with someone who doesn’t comprehend what I said to begin with in this thread.
I didn’t say that the poster shouldn’t check anything.

 

I think I comprehend ok. You were defending the use of steering dampers, no?
Some guys advised adding a steering damper as a solution to the OP's problem, which turned out to be more than likely caused by wear/maintenance related issues. A damper would have hidden the problem and allowed it to get worse, maybe to the point of failure. Not a good result...
No arguement from me about the supposed virtues of steering dampers being used in the correct application.
I just don't think that this case was the correct application.

 

The original poster solved his problems by checking everything and finding some loose components that needed tightening up.

That’s a successful conclusion and the rest is just speculation and opinion.
No need to continue.

 

Straight axles are problematic. Sometimes even the perfectly set up front ends will wobble! The correct way is to set the front end as to eliminate the wobble…..then add the stabilizer…..for insurance! Usually if a front end is set up correctly and there is still a wobble, change the caster! I said “ change” either add or subtract caster! Your problem will go away……then diddy bop down to Orielys and get a stabilizer! Be happy!





Bones

 

No, the fix is to replace the worn components, not put a bandaid stabilizer on it.

 

If they wobble they weren't "perfectly setup". No reason a straight axle should ever wobble if done correctly. I've lost track of how many I've done since 1968 and only one I had trouble with was my very first axle swap I did on my '57 Chevy. Once I figured out my mistakes it drove perfect, as have all others since then I did.

 

I have been involved in many, many straight axle situations, not hot rods but trucks. A straight axle is a straight axle! I have seen many factory straight axles that were perfect condition and perfectly aligned, and still had the wobble! Shops would just tell folks they have to live with it! They would bring them to me , I would take a degree out of the caster, maybe even out of spec, but the problem would go away! Just my experiences maintaining a fleet and local truck owners. I am just giving my experiences, over the thirty + years I maintained the fleet. Folks can take it or leave it!




Bones

 

When I bought my off topic jeep, I put a 4" lift and 10" wheels with 12" tires on it.
Developed a horrible wobble at 25 mph and you would have to come to a stop because you couldn't hold the steering wheel.
Took it to the alignment shop and we couldn't find anything wrong. checked steering box, tie rods , steering dampener, toe in and caster.
Mechanic said sometimes you just have to throw parts at it until it's fixed.
He suggested that I replace all the tie rods with a tie rod kit.
Replaced all the tie rods, ends and problem solved. Couldn't find anything wrong with the ones I took out.

 

When you raised the Jeep, you changed your caster, that is what caused the wobble. Changing it back to before, or changing it a little one way or the other would have fixed your wobble with changing good parts. Maybe!




Bones