Death wobble

[TomT/Williamsburg]

Originally Posted by RalphM

No wishbone ball, their split, caster is about 6-1/2 to 7 degrees. The tie rod ends are new, and so are the wishbone ends.
As much as it might help, I'm hesitant to put on a stabilizer. My car is a traditional hot rod, built as if it would have been in the early to mid fifties. Something like that would be too much out of place.
Right now the newest part I have is a 56 steering box.

Are you running a panhard bar?

[quickchange34]

If all of your front end parts are good put a VW steering damper on it , they are easy to install. You will be glad you did.

[FlatheadTed]

reverse eyes ? a spring relies on tension to keep the axle stable ,Henry used stiff shackles for a dampening affect .Ted

[RalphM]

No panhard bar, yes, reversed spring eyes. And the front spring/shackle bushings are the metal with rubber type.
Of course those were such a pain to put in I cheated with the rears and used the insert type.

[32phil]

I've been fighting the death wobble for a long time...on several cars...
I 've tryin' this and tryin' that....&.. tweakin' this and tweakin' that.
Everrrrry once in a while it will happen ... always after making a turn and only when the road is a little "lumpy"....
I think I'm going to put a damper on and see if it helps....
If it does cure it ...I'm going to slap myself for waiting so long....
Actually....
I'm going to have to get on line cause I waited too long on a lot of stuff....
just sayin'

[trainguy]

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Originally Posted by 32phil

I've been fighting the death wobble for a long time...on several cars...
I 've tryin' this and tryin' that....&.. tweakin' this and tweakin' that.
Everrrrry once in a while it will happen ... always after making a turn and only when the road is a little "lumpy"....
I think I'm going to put a damper on and see if it helps....
If it does cure it ...I'm going to slap myself for waiting so long....
Actually....
I'm going to have to get on line cause I waited too long on a lot of stuff....
just sayin'

Phil,You will not regret it.Phil

[Dennis (EV8G)]

Originally Posted by RalphM

I have the early style drag link with the spring loaded ends. Maybe it's worn in enough to need adjustment.

If the tie rod end plugs are not turned in with enough pre load on the springs this can absolutely cause the wobble or shimmy you're experiencing. I have had first hand experience with this being the cause. The tie rod basically turns into a Pogo Stick.

I thread the plugs in until the springs are fully compressed, back the plugs out to the first available alignment of the cotter pin slot then back the plugs off another 360 degrees. If the steering feels too heavy you can continue to back the plugs out 180 degrees at a time to lighten the steering but if the shimmy comes back you've gone too loose on the spring pre load.

Keep in mind that any change to the plugs (either screwed in more or out less) will affect your toe setting so you will need to reset the toe after you adjust the tie rod ends. If you have an adjustable drag link that also means you will need to adjust it to get the steering wheel back to the center position.

[FlatheadTed]

A reversed eye spring can drop the shackle from say 30deg down to 10 deg were there is not tension on the spring so you get a seesaw teta/ tota affect were the axle can go side to side ,You can have a dead man link at one end that can stop that .or you shorten the spring so a jack is needed to put the shackles in .I had a bad shimmy and had backed out the control arm plugs as Dennis is describing but also found a small bit of play in the front wheel bearing I sorted those two issues and it seem to settle down .After that I got someone to wiggle the steering wheel while I looked under neath and that's when I found the rubber wish bone ball loose .It can two things working together .Ted

[AKCJ]

Ralph - I've had bad death wobble on one of my rigs and it can really be scary. To find the problem I ended up grabbing the front bumper and pulled the front of the vehicle side to side while watching everything in the front end. Works better with two (or more) people. Anyway, my problem turned out to be loose U-bolts (leaf spring to axle).
Good luck.

[JSeery]

One thing is for sure something has to be loose somewhere. That is what allows the play to develop into the shake as it reaches a harmonic.

[zippi]

I know this an old thread but the death wobble has me concerned now. It happened to me shortly after I got my 37 Ford pick up and it happened twice today. Stock frame, reverse eye spring, disk brakes. I put new shocks on the first time it happened. I have new tires on the front. The wife said she doesn't feel safe in the pickup. I think it happens when one front tire hits a hole. I think all 3 times I was going about 40 or 45 mph. What would be some of the simple things that I can check.

[hardtimes]

Originally Posted by zippi

I know this an old thread but the death wobble has me concerned now. It happened to me shortly after I got my 37 Ford pick up and it happened twice today. Stock frame, reverse eye spring, disk brakes. I put new shocks on the first time it happened. I have new tires on the front. The wife said she doesn't feel safe in the pickup. I think it happens when one front tire hits a hole. I think all 3 times I was going about 40 or 45 mph. What would be some of the simple things that I can check.

If you've read this entire thread, you get the idea that everything has to be in spec and sufficiently tightened. Any (seemingly) little noticed or overlooked loose/worn part or poor adjustment will contribute...to the eventual harmonic setup. I start with tire pressure/balance, then wheel bearing adjustment , then on/on.
I like the 'vibration dampener' use idea, but have always thought that that was band aid, masking something that's starting to get out of spec.

I'd like to ask any who knows....CAN slightly out of round/not trued wheel rim start/contribute to death wobble . I think the answer is yes.

[RalphM]

I'm going to put a steering stabilizer on and see if it helps. It may not be traditional, but if itt stops it, who cares.

[zippi]

Thanks for the input guys.

[32phil]

I'm going to go out on a limb here and say I think the cause of the death wobble is the lowered springs/dropped axles. On my original cars with stock front ends, as long as all the parts are new/rebuilt and everything is tightened/aligned properly the car is fine. On the Hot Rods EVERYTHING is new, tight and lined up properly....AND....Death Wobble happens. I have a Brookville roadster( see it on my Instagram page.. 1932 Phil) on an original frame, flathead drive train with a stock uncut wishbone. The rear spring is a POSIE with several leaves removed and the front is a reverse eye POSIE. The axle is a dropped 4'' drilled Superbell. 7.50X16 tires in the rear and 6.00X16 in the front. The car has a pretty good "rubber rake" and mechanical one as well. Enough of a rake that the lube runs DOWN the torque tube to the trans when the car is on level ground. I think with a rake like that, it changes the caster and causes the front end to wobble. We have another car with split hair pins the same rake and the front end shop brought the caster in by adjusting the hairpins. Can't do that with a stock wishbone.
OK guys ....Let's hear what y'all think of my theory....

[JSeery]

Originally Posted by 32phil

I think with a rake like that, it changes the caster and causes the front end to wobble. We have another car with split hair pins the same rake and the front end shop brought the caster in by adjusting the hairpins. Can't do that with a stock wishbone.
OK guys ....Let's hear what y'all think of my theory....

First off, yes you can adjust the caster. It is done by pie-cutting the radius rods to get the angle you want.

What do I think of your theory? Thousands and thousands of hot rods with dropped axles, reversed eye springs, etc. preform great without front end wobble and lot of totally stock cars/trucks have a major problem. It requires proper front end geometry, proper components and proper fit to work properly. Front end wobble is often traced to tires, rims and loose hub bearings and so on. Hard to blame that on dropped axles!!

Any solid front axle has a tendency toward front end wobble if everything is not kept in VERY good condition. That is the reason many later model cars and trucks came with dampers installed at the factory.

[willowbilly3]

I agree that it shouldn't happen to a car that everything is "right" with. But, that being said, every new Jeep or other 4x4 with a solid axle comes right from the factory with a steering stabilizer. In my lifetime as a mechanic, I have had to resort to a steering stabilizer a few times and one is on my hotrod with split bones. I had everything new, alignment done and it would still do it when I hit those bridge seams that are on a diagonal.

[zippi]

I jacked the front end up and there is just very little play in the steering wheel. I grabbed each tire at the top and bottom then side to side and and pushed and pulled on it and didn't feel any play anywhere. The ball joints feel nice and tight and the drag link is good and tight. I've got the two front tires in my truck and I'm going to drop them off tomorrow after work to have them re-balanced. Guess I'll start with the easy stuff first.

[hardtimes]

Originally Posted by zippi

I jacked the front end up and there is just very little play in the steering wheel. I grabbed each tire at the top and bottom then side to side and and pushed and pulled on it and didn't feel any play anywhere. The ball joints feel nice and tight and the drag link is good and tight. I've got the two front tires in my truck and I'm going to drop them off tomorrow after work to have them re-balanced. Guess I'll start with the easy stuff first.

If you have un-split front wish bones, make certain to check the BALL for correct tension.
I had the wobble and was at a loss to find a reason. I rechecked the ball and found that it was looser than it should be. I tightened it and that helped considerably.
Good shocks are absolutely necessary also for front end control.

[zippi]

Originally Posted by hardtimes

If you have un-split front wish bones, make certain to check the BALL for correct tension.
I had the wobble and was at a loss to find a reason. I rechecked the ball and found that it was looser than it should be. I tightened it and that helped considerably.
Good shocks are absolutely necessary also for front end control.

I just put new Monroe shocks on a few months ago. The ball on the wishbone near the center of the frame I assume you are talking about?