Steering wheel wobble
- Thread starter grumppyoldman
- Start date
RalphM
Well-known member
32 Phil,
What would optimum caster be on a car with some rake?
My AV8 has a dropped front axle, big and Little’s, and I set my caster at 7 degrees. I thought that was plenty, but I too get the death wobble when I hit the right rut in the road. It does not stop till I come to a dead stop. All parts being new, or rebuilt, I’m thinking the VW stabilizer is the way to go. In fact I bought one and just have not installed it yet. Do I need more caster?
Mrfliboy I like your mounting idea.
What would optimum caster be on a car with some rake?
My AV8 has a dropped front axle, big and Little’s, and I set my caster at 7 degrees. I thought that was plenty, but I too get the death wobble when I hit the right rut in the road. It does not stop till I come to a dead stop. All parts being new, or rebuilt, I’m thinking the VW stabilizer is the way to go. In fact I bought one and just have not installed it yet. Do I need more caster?
Mrfliboy I like your mounting idea.
JSeery
Member Emeritus
5 to 10 degrees with 7 being considered a good target. It is most likely something else causing the issue. Need to check each component of the front end. Best bet might be to start a new thread on the topic. Nothing wrong with installing a damper, but you really need to locate the weak link(s) that are causing the problem first.
A bones
Well-known member
Van, camper, or microbus.
To JSeery
Please understand I'm not looking to start a fight here.
I'm in the same boat as RalphM
I have a mild Hot Rod. Everything is new or 100% rebuilt including the steering box. All the hardware is tight and the front end has the proper toe in/out. Tire pressure is correct as well. The car was built with no expense or effort spared.
You say it is a geometry issue, I agree.....what do you think the problem is specifically ?
Please understand I'm not looking to start a fight here.
I'm in the same boat as RalphM
I have a mild Hot Rod. Everything is new or 100% rebuilt including the steering box. All the hardware is tight and the front end has the proper toe in/out. Tire pressure is correct as well. The car was built with no expense or effort spared.
You say it is a geometry issue, I agree.....what do you think the problem is specifically ?
JSeery
Member Emeritus
The spindle moves in a different arc that the steering arm. I'm assuming you have side steering. It depends on how your front suspension is set up, but in any case when the components move up and down if different parts are on a different arc the steering has to move to make up the difference. To know what exactly is going on in your situation you would have to describe your setup in detail.
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Talkwrench
Well-known member
Yup it will scare the **** out of you.. as Ive written before it happened to me on -then a newish 3 T Mitsubishi truck driven it from new with tens of thousands of miles on it and in good condition then just out of the blue on the freeway it happened ..sweet geezus!! So it's a problem with straight axles not just an early Ford.
Never use a damper to cover a problem , however I recommend them for insurance... Cheap and easy to do with a VW one .
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JSeery
Member Emeritus
Had a few later model Ford trucks scare the hell out of me!Here's an update to my previous postings about Death Wobble issues.
The specs on the car:
My car is a Brookville 32 Roadster on an original 32 frame. No fenders, dropped and drilled Superbell front axle, Posies lowered front spring. Stock un-cut wishbone, early Model B rear end, Posies rear spring with 4 leaves removed. Coker Classic 750-16 tires on the rear 600-16 on the front. Warmed up 8BA with 39 trans L/Z gears.
The car is new or completely rebuilt, with the best of everything front to back. Toe in is at a little more than 3/16.
I would experience the death wobble only on low speed turns. RXR crossings were a killer. I would have to slow to crawl and then it would still get a little "nervous".
Yesterday I installed a So Cal steering damper. It's a different car. I tried every pothole and bump along with every RXR crossing multiple times.....no death wobble !!. I could feel it for a split second.... it would seem like it wanted to... but it would straighten out immediately. I'm good with it for now. My plans are for a new steering arm from So Cal, it's dropped down some from the one that is on the car now. Jseery pointed out that the extreme angle of the drag link may be a problem as well. Also I'm investigating the caster and if we can change it if it is off spec.
Thanks for the feedback......stay tuned.
The specs on the car:
My car is a Brookville 32 Roadster on an original 32 frame. No fenders, dropped and drilled Superbell front axle, Posies lowered front spring. Stock un-cut wishbone, early Model B rear end, Posies rear spring with 4 leaves removed. Coker Classic 750-16 tires on the rear 600-16 on the front. Warmed up 8BA with 39 trans L/Z gears.
The car is new or completely rebuilt, with the best of everything front to back. Toe in is at a little more than 3/16.
I would experience the death wobble only on low speed turns. RXR crossings were a killer. I would have to slow to crawl and then it would still get a little "nervous".
Yesterday I installed a So Cal steering damper. It's a different car. I tried every pothole and bump along with every RXR crossing multiple times.....no death wobble !!. I could feel it for a split second.... it would seem like it wanted to... but it would straighten out immediately. I'm good with it for now. My plans are for a new steering arm from So Cal, it's dropped down some from the one that is on the car now. Jseery pointed out that the extreme angle of the drag link may be a problem as well. Also I'm investigating the caster and if we can change it if it is off spec.
Thanks for the feedback......stay tuned.
Karl
Well-known member
For what its worth I have just spend months fixing the death wobble on my 34 This is the process nothing worked until the last step
1. Tightened all the draglinks and tire rods
2. Replaced the front spring which had a cracked main leaf
3. Replaced the Spring hanger bushings
4.Replaced the worn rubber ball on the wishbones
5.Replaced the worn rubber balls on the shock links
6. Replaced the front shocks (both of which where doing very little )
7. Checked the steering box attachments
and finally inflated the tires to the correct pressure and checked and correctly adjusted the toe in which was set at greater than 1/4 inch -The last step fixed it completely -I'm sure all the other steps have improved the drivability of the car and were necessary but it was the toe in correctly adjusted that fixed the death wobble -Karl
1. Tightened all the draglinks and tire rods
2. Replaced the front spring which had a cracked main leaf
3. Replaced the Spring hanger bushings
4.Replaced the worn rubber ball on the wishbones
5.Replaced the worn rubber balls on the shock links
6. Replaced the front shocks (both of which where doing very little )
7. Checked the steering box attachments
and finally inflated the tires to the correct pressure and checked and correctly adjusted the toe in which was set at greater than 1/4 inch -The last step fixed it completely -I'm sure all the other steps have improved the drivability of the car and were necessary but it was the toe in correctly adjusted that fixed the death wobble -Karl
grumppyoldman
Well-known member
Well I just got through installing a So-Cal steering damper, no help. Adjusted the toe-in to 1/4" no help. Removed the front Oldsmobile spinner hub caps, no help. Going to change toe-in ti 1/8", now i'm getting pissed, every thing is tight. Don't know about the original shocks, don't know which way to turn adjustment to stiffen them up. Maybe some of you can help me on that. Al
grumppyoldman
Well-known member
Done all of that already, grasping for straws now, thought the shocks might have something to do with the shimmy, it's not a wobble like you guys have explained. It will stop when I either go to 70 mph or when I slow down to 55mph. I'ts in one range of speed and I'm about out of tricks. Al
rotorwrench
Well-known member
The older vehicles with king pins on straight axles are more susceptible to spindle control oscillation that later cars with A-arm & ball joint spindle mounting due to the short distance between the bearings in the spindles. Any vehicle with the king pin type steering knuckle can experience it. Always try a different tire known to be free of problems on there and see what happens. I'd bet it solves the problem as long as the front end is properly adjusted for caster, camber, and toe in. Those old front axles do flex a bit while your driving and you want a bit of toe in left after they start to flex at higher speed.
Any looseness in the bearings and control rods allow the oscillations to get started but they aren't always the cause of it. Tires with poor carcass design, a carcass that was incorrectly layered in the manufacturing process, or a delaminated carcass are the number one cause of this problem. The tire can flex a lot more than any of the vehicles steering components and once it gets started, that's what shakes the crap out of everything. One side is literally fighting the other for control.
I've heard a few horror stories about how fast the needle bearing type king pin bearings can deteriorate and fail. I know they sound like a good idea but I don't think they are up to the task on the average king pin steering design for light vehicles. The load factor is too high for the diameter of the individual needle bearing rollers. Needle bearings are used in some of the helicopter main rotors I work on but they are huge by comparison and they have to be replaced on an average of every 2000-hours in service on the smallest of them. I would prefer the bushings myself. They were good enough for Grandpop so they are good enough for me.
I don't blame someone for using a steering damper due to the fact that a tire can break down at any time. It is a form of insurance but it might add to steering load making U-turns a little more difficult to manage.
Any looseness in the bearings and control rods allow the oscillations to get started but they aren't always the cause of it. Tires with poor carcass design, a carcass that was incorrectly layered in the manufacturing process, or a delaminated carcass are the number one cause of this problem. The tire can flex a lot more than any of the vehicles steering components and once it gets started, that's what shakes the crap out of everything. One side is literally fighting the other for control.
I've heard a few horror stories about how fast the needle bearing type king pin bearings can deteriorate and fail. I know they sound like a good idea but I don't think they are up to the task on the average king pin steering design for light vehicles. The load factor is too high for the diameter of the individual needle bearing rollers. Needle bearings are used in some of the helicopter main rotors I work on but they are huge by comparison and they have to be replaced on an average of every 2000-hours in service on the smallest of them. I would prefer the bushings myself. They were good enough for Grandpop so they are good enough for me.
I don't blame someone for using a steering damper due to the fact that a tire can break down at any time. It is a form of insurance but it might add to steering load making U-turns a little more difficult to manage.
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