The Death Wobble

OK, good, glad to see its probably fixed.. I asked what I did because of all the suggestions and all the work that was performed.. Its nice to hear its fixed now,, but,, it could have probably been done a lot sooner if the early suggestions had been followed.. Thats all I'm trying to say,, I'm not trying be an a^#$^%$^..
 
fordgarage said:
Install the Tie rod link hardware properly.
Install the drag link hardware properly, and the drag link in the correct F/R position.
Set the toe in properly.
Click to expand...

I agree with these being the first or main cause of the "death wobble". My temporary front end is so worn that if I jack up the front axle I can grab the tires at the tops and move them in and out about 2", but I've never had a hint of the shakes, or "death wobble". After I reassemble my original front end and reinstall it, the car should steer itself. :D LOL
 
I had this happen on my Model AA truck yesterday. The truck had been sitting for awhile. The front brakes had not fully released, after several stops from 10 miles per hour, the brakes "loosened up" and the probelm went away. Also it took a couple of miles for the flat spots to even out on the tire. The tires are new and the air presuure is at 35 psi.

John G
 
During my last tour and a couple of weeks earlier I noticed an occasional wobble. It would happen like others at slow speeds often after hitting a small pothole while turning etc.
At higher speeds it went away. I had adjusted the steering earlier and removed some of the play but still too much.

I had completed front brakes conversion to Cast Iron. During the tour I noticed end play in both front wheels.

1. Bearings needed to be one notch on castle nut tighter. (No more end play and still free wheels)

2. While I thought the Pitman Arm was tight IT WAS NOT!
I took an awl and scribed a mark across the face of the harm and pivot. I then could move steering with wheel off and moved slightly. The marks moved and did not line up! Hardly any movement but enough where I was able to tighten the castle nut 2 notches!

3. Turned in the end caps on drag link 1/2 turn.

Result: Less than 2 " play in steering wheel and NO more wobble.

Next I will double check toe in

LIKE ALL THE OTHER POSTS GO TO BEARINGS AND CHECK THAT PITMAN ARM !
 
We put a stabilizer on a lady's Model A and it worked perfectly. I did notice a little more effort turning into a curve but it did certainly eliminate the wobble. My Volkswagens came with a stabilizer and when it wore down the wobble would show up so there must be something to it.
 
WOW! This is an old thread. (9/28/12)

The question with "death wobble" is do you want to fix the symptom or do you want to fix the root problem? Ever wonder why one Model A with everything worn and loose in the front end does not wobble, yet another A with one little thing slightly loose shimmys like crazy?

To fix the symptom just make sure everything in the front end is a tight as possible. Then keep your fingers crossed. You are only holding tight a wheel that wants to shimmy.

To fix the actual problem so the wheels do not want to shimmy in the first place there is really no mystery. If it shimmys something is usually BENT affecting caster. Tightening everything up to new spec certainly improves steering and tracking but does not address geometry errors that induce resonance like shimmy. If you have a bent axle, bent forgings at either end of the wishbone, engine misalignment (the wishbone bolts to the fly cover casting at the back) or frame twist and bend you do not have the factory spec 2 degrees caster. Simple visual inspection likely will not reveal a bend of only a degree or two. You need to carefully measure.

Think of a shopping cart. When the front wheels get slightly bent back from slamming curbs and parking lot divots, you get a cart with a front wheel that goes into the dreaded "death wobble".

80 years of pounding pot holes and RR tracks bends both the axle, shackles, and wishbone in the negative direction. Reducing caster just one degree from the factory sped 2 degrees will make wheels want to shimmy.

There is a lot of info out there about how to straighten an A axle, but not much about the wishbone. The front forgings that hold the kingpin actually bend rather easily compared to the axle. Perhaps someone has the Ford print for the wishbone and can throw in a few angles and dimensions?

dia%20c.jpg
 
Mike, I know so little about front end geometry, this explains a lot. Next, could you give us the terms,explanations, and numbers. I hope I'm not asking too much, but I don't know where to get this info. Thanks for posting this.
Terry



MikeK said:
WOW! This is an old thread. (9/28/12)

The question with "death wobble" is do you want to fix the symptom or do you want to fix the root problem? Ever wonder why one Model A with everything worn and loose in the front end does not wobble, yet another A with one little thing slightly loose shimmys like crazy?

To fix the symptom just make sure everything in the front end is a tight as possible. Then keep your fingers crossed. You are only holding tight a wheel that wants to shimmy.

To fix the actual problem so the wheels do not want to shimmy in the first place there is really no mystery. If it shimmys something is usually BENT affecting caster. Tightening everything up to new spec certainly improves steering and tracking but does not address geometry errors that induce resonance like shimmy. If you have a bent axle, bent forgings at either end of the wishbone, engine misalignment (the wishbone bolts to the fly cover casting at the back) or frame twist and bend you do not have the factory spec 2 degrees caster. Simple visual inspection likely will not reveal a bend of only a degree or two. You need to carefully measure.

Think of a shopping cart. When the front wheels get slightly bent back from slamming curbs and parking lot divots, you get a cart with a front wheel that goes into the dreaded "death wobble".

80 years of pounding pot holes and RR tracks bends both the axle, shackles, and wishbone in the negative direction. Reducing caster just one degree from the factory sped 2 degrees will make wheels want to shimmy.

There is a lot of info out there about how to straighten an A axle, but not much about the wishbone. The front forgings that hold the kingpin actually bend rather easily compared to the axle. Perhaps someone has the Ford print for the wishbone and can throw in a few angles and dimensions?

dia%20c.jpg
Click to expand...
 
I would take the car to a good Wheel alignment shop and get them to check the Caster. This what usually causes this problem. It could be something like a worn radius ball or a bent axle. Check and take the spec's with you. Caster is usually between 3 and 6 Degrees.
Ask the shop if they have the tools to bend the axle to get the Caster. Truck shops and Good Alignment shops will have these tools. Like Denis4x4 said check the wheels for true.

John Poole
 
Gotta say, I've never hear Model A guys refer to it as the "death wobble". I thought it was just a Jeep thing haha
 
hale1776 said:
Has anyone else had the death wobble, but only in the right tire.... makes no sense.
Click to expand...

Yes, I was following one of the cars in our club and noticed that only one wheel went into the death wobble. I need to check back with the owner to see if he found anything yet.
 
Just put an ez-steer Teflon coated bronze bushing set in drag link and tie rod, tightened everything up tight...one original spring was broken......called local alignment shop to get toe in set and he told me his computer screen wouldn't even turn on until he entered year, make and model..so still looking. Going to set toe in between 1/16th and 1/8th per service bulletin. I also swapped ends on drag link for same reason. Could have made a three stooges short of my son and I trying to get a new cartridge into a modern grease gun, much swearing, grease, and paper towels, got gease to come out everywhere except the end of hose.
 
hale1776 said:
Just put an ez-steer Teflon coated bronze bushing set in drag link and tie rod, tightened everything up tight...one original spring was broken......called local alignment shop to get toe in set and he told me his computer screen wouldn't even turn on until he entered year, make and model..so still looking. Going to set toe in between 1/16th and 1/8th per service bulletin. I also swapped ends on drag link for same reason. Could have made a three stooges short of my son and I trying to get a new cartridge into a modern grease gun, much swearing, grease, and paper towels, got gease to come out everywhere except the end of hose.
Click to expand...

he can enter any car into the machine then set the toe to specs for the A..
if they dont know how to bypass that section then run
 
Just wondering, some "MODERN" vehicles have STEERING STABILIZERS! Did NOT the manufacturer design stuff correctly & added a HUGE "BANDAID"??????????????????????????????????????????????-----------------------??????
Bill W.
 
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