Possible causes of slow speed (5-15 mph) death wobble

[Tim Ayers]

My '28 AV8 rides on a '32 chassis with a stock front end (except of tube shocks) with a '32 box.
When built, spindles were fitted with NOS king pins and bushings and honed on a Sunnen machine.
Drag link and tie rod ends were fitting with NOS springs and ball ends.

Twice this week, I experienced the dreaded death wobble at very low speed (once at 5 mph and the other at around 10-15 mph).

Both times it seems to have come from the driver's side wheel hitting a deep pothole while pulling into a lot.

Oddly, it has not this done it at speed. After the second time it happened, I tried to avoid any dips in the road while at speed, but of course that's not possible. I was surprised after hitting a deeply recessed manhole cover that it didn't do it.

I've had the death wobble happen in other Ford cars at speed, but never at the low speeds like it happened in my car.

Of course I'm going to jack up the front end and check everything out, but curious if anyone has some thoughts on what to ensure I pay close attention to.

Thanks,

[Krylon32]

Tim: I built 100's of 28-34 straight axle chassis during my 40+ years in business and have had a few with death wobble. All of these chassis used basically the same time tested new components with the proper geometry. I've only had a few with death wobble and that was usually caused by the customer not having everything adjusted right. I also think tires come into play. The worst death wobble I ever had was a 32 roadster I built using a Schroeder side steering box. Everything was adjusted right with 7 degrees of caster and 1/8th of toe in plus the Excelsior radials had 35 lbs of air in them. I finally contacted the Bones who had done quite a few this way and they said the only solution they found was a front end stabilizer. I know these are Poo-Poo on here but when I have used them successfully. Also the majority of the chassis I built never had a wobble problem. Check the heading death wobble on here, lots of opinions. I currently have 4 straight axle deuces and my 40 coupe in the museum and they all have stabilizers, not to solve a problem just because I feel they smooth out the road feedback a little bit.

[Tim Ayers]

Originally Posted by Krylon32

Tim: I built 100's of 28-34 straight axle chassis during my 40+ years in business and have had a few with death wobble. All of these chassis used basically the same time tested new components with the proper geometry. I've only had a few with death wobble and that was usually caused by the customer not having everything adjusted right. I also think tires come into play. The worst death wobble I ever had was a 32 roadster I built using a Schroeder side steering box. Everything was adjusted right with 7 degrees of caster and 1/8th of toe in plus the Excelsior radials had 35 lbs of air in them. I finally contacted the Bones who had done quite a few this way and they said the only solution they found was a front end stabilizer. I know these are Poo-Poo on here but when I have used them successfully. Also the majority of the chassis I built never had a wobble problem. Check the heading death wobble on here, lots of opinions. I currently have 4 straight axle deuces and my 40 coupe in the museum and they all have stabilizers, not to solve a problem just because I feel they smooth out the road feedback a little bit.

Thanks, Gary. This issue is new to the car. Since built, I've hit various pot holes due to the poor state of NJ's roads and this hasn't happened before this week.

Curious, how did you attach the "dead end" of the stabilizer to the front end? The ones I've seen either have steel loops on both ends or a stud on the "dead" end. I'd really prefer not to drill into the axle.

Ironically, the front axle is really nice and I got it from you. LOL!!!!

[Seth Swoboda]

I see this issue come up from time to time. I also see issues arise with folks who have modified V8 engines with multiple carbureators, a different camshaft, ect. I wonder if during these custom builds, if enough research was done to figure out if I change something, what effect will it have on other functions? I've thought about this a lot. If you change one item, for instance the dropped axle, how does that one change alone effect the steering and handling? Now change the steering box and maybe the drag link, have I compounded a problem? It takes a small amount of engineering to make sure all those modifications will give you good results. Some of the experienced hot rod builders have that knowledge and expertise.

[Tim Ayers]

Originally Posted by Seth Swoboda

I see this issue come up from time to time. I also see issues arise with folks who have modified V8 engines with multiple carbureators, a different camshaft, ect. I wonder if during these custom builds, if enough research was done to figure out if I change something, what effect will it have on other functions? I've thought about this a lot. If you change one item, for instance the dropped axle, how does that one change alone effect the steering and handling? Now change the steering box and maybe the drag link, have I compounded a problem? It takes a small amount of engineering to make sure all those modifications will give you good results. Some of the experienced hot rod builders have that knowledge and expertise.

Thanks, Seth. To be clear, the front end is stock '32 Ford. Nothing is dropped. Axle, tie rod, steering box, spindles, drag link & pitman are all in their stock location and as from the factory.

Motor is most definitely not stock though.

[Krylon32]

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Tim: I doubt if the motor is the problem. On a stock 32 front end I attach one end on the tierod and the other on the wishbone. I had a local machine shop machine a sandwich style clamp that went on the tierod and held the stationary end and unfortunately I had to drill a couple 5/16 holes thru the wishbone to hold a simple piece of flat I'd tig welded the provided tab to. Also I had one of Neal's Hudson steering boxes but a stock deuce box should work fine also. No pictures as the truck sold quickly. Drove great.

[Karl Wolf]

I first drive the A-V8 with old tires- mud in one- out of balance, a lot.
New tires, stabilizer from a a (1975?) VW super Beatle.
Welded a tab on the left side of the wishbone, other end made a clamp to the tie rod.
Karl

[34fordy]

Is this problem more common with the vehicles prior to 1935 when Ford changed to a cross-steering box? I remember that happening twice on a 34 I owned. I was sure that I had too much "slop" or clearance but could not find it. The only thing I changed was the adjustment of the draglink. I wondered if more caster would have helped. For some reason it quit happening and I could not understand why.

[highbeams]

How do you change the adjustment on the draglink? My '33, obviously original, draglink = very sloppy. I bought NOS pitman arm and draglink parts from John @ AllFord.
Still could be a tad tighter draglink.
These '33, '34, '35s need the 1949/50 F100 'update' including the steering box, of course.
Possibly a credible hot rod shop can do that. My son had that 'wobble' around town t'other day.


Also gotta work on the pre-dawn wobble to the bathroom . . . . .

[34fordy]

[QUOTE=highbeams;2249186]How do you change the adjustment on the draglink?


With respect:
With your draglink socket. I believe there are numerous threads on this very subject. How would you know for sure that a 90 year old car never had some parts replaced?

[fordor41]

check play in steering box. I installed a saginaw steering box in our '41 ford and first time out it scared me to death it shook so bad. took slop out of the box and good to go.

[highbeams]

[QUOTE=34fordy;2249206]

Originally Posted by highbeams

How do you change the adjustment on the draglink?


With respect:
With your draglink socket. I believe there are numerous threads on this very subject. How would you know for sure that a 90 year old car never had some parts replaced?

You're right, appears never been touched.
But as said, replaced w/NOS parts, screwed in the draglink screw to the max, of course, w/NOS pitman arm. (my pitman arm ball slightly worn . . . pics avail if interested.
Also the tie rod end replaced. But swiftly turning the steering wheel left to right /right to left, there still is a 'knock'. So, Iam considering using more washers, the leftovers from my old parts. Have more washers been a 'remedy'?

These steering boxes have little 'adjustment'.
Frustrated with Ford's steering, I posted a comment/question, How could Ford compete with GM regarding this? A reply, GM was worse!

*****

[deuce_roadster]

The stock components have (supposed to be round) balls that spring loaded parts connect to with a large screwdriver style adjustment. 90 years later 2 parts of the "ball" got more wear than the rest and the round ball becomes football shaped, especially when not greased properly over time, especially early pittman arms. One of the springs that holds tension on the ball could have broken too. There can be play with the wheels in one position and none in another. I always check those with the wheels in all positions. Also as Seth stated, play or wear in the steering box I would check first. I have seen cracked worm gears seem to steer fine until turning a corner. This stuff is all old unless built with NOS parts recently. Your life depends on the steering and brakes working properly. Should be NO compromises with these components.

[Automotive Stud]

I had a similar problem with my roadster on a '32 frame. It turned out my axle was egged out where the kingpins go through. It felt tight until I loosened the pinch bolt and then I could feel a lot of wobble in it. I have an old chrome dropped axle, so I didn't want to heat it to peen it back, so I reamed out the axle holes and pressed in a bushing, then honed the bushing with a kingpin reamer. Worked out perfectly.

[Tim Ayers]

Originally Posted by Automotive Stud

I had a similar problem with my roadster on a '32 frame. It turned out my axle was egged out where the kingpins go through. It felt tight until I loosened the pinch bolt and then I could feel a lot of wobble in it. I have an old chrome dropped axle, so I didn't want to heat it to peen it back, so I reamed out the axle holes and pressed in a bushing, then honed the bushing with a kingpin reamer. Worked out perfectly.

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.

[petehoovie]

Originally Posted by Tim Ayers

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.

[NealinCA]

Originally Posted by Tim Ayers

Follow up:

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.

I had the same issue on one of my cars and the special washer cured the problem.