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

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,

 

This has been discussed here , there & everywhere ! You'll get every conceivable thought thrown at the wall to see if it sticks ! Truth is , its caused by different things in different cars , try TIRES first !

 

normally if it starts after hitting a pothole it would be a loose or failed component if it starts at speed it would be related to tire or wheel ( balance )and would happen at the same speed every time

 

Easy check is to swap the tires

 

I agree with loose or sloppy components but also caster. The last car at my shop that had that problem only had three to four degrees caster and when I set it up to 10 all the problems went away

 

Thank you. I just checked and it's got a little of 4 degrees. Curious how do you adjust it? With a shim?

 

^^^^
Needs more ,
My stock 32 with 4 inch drop would do @ very low speed like described ,
Had to increase caster
More toe out
Wish bone ball added shim to tighten up
& some adjustment on original tire rods ends
& box adjustment

It just added up ( free movement )

 

Like mentioned, check all components for looseness, check tires for out of round and balance and alignment. If your car still wobbles change your caster! This will fix it!





Bones

 

yes, tapered shim.

 

Had that happen to me on a 40 chevy... turned out the welds on the steering gear box to the frame was cracked... re welded and she was solid as a rock

 

The easiest, quickest fix to try would be adding a " tie rod to frame" steering damper.

 

A steering damper isn’t really a “fix” .

I had this issue with my 32 on stock 32 front end inc steering box , the culprit was play in the taper tie rod ends going into the spindle . Only happened at a particular speed when the harmonics in the front end all aligned to make it happen .

 

My roadster never had that problem after caster was adjusted 25 years ago. Then I changed to an aluminum radiator (much lighter) and now, with the front end slightly higher, I do have this problem sometimes.

 

Nope , not an acceptable fix for some ," they" won't be appeased until you chop the front end off & replace with all genuine , cost you a fortunes, name brand ,made in mom & pop shops , only in this country , engineered for your application , 500% overkill parts , that should make the critics happy , or at least quiet them momentarily ! For the record a steering stabilizer is not a " repair" ,its an Improvement !

 

So if there is a loose or worn part, a steering stabilizer would be a fix?
Why are so many so defensive of certain "mods" as an answer regardless of the actual problem? Serious question.

 

Too much scrub radius!
Too much caster! [in a lightweight vehicle]
Split bones with the wrong shackle angle [this can be OK with a panhard bar]

 

If this is something that has just suddenly started happening it might be a warning. Be aware that it could possibly be a sign of something damaged or about to fail. I hope this is not the case, but check everything out properly before whatever it is breaks. Better to be safe than sorry.

And as for a steering damper, it should be a "last resort" kind of thing. It will only mask the cause of the problem. Make damn sure if you fit one it is not masking a potential catastrophic failure.....

 

Steering damper is not fix for worn parts. All my cars have them and the front ends are tight.

 

Fresh build or old build with some miles on it,
What wheels and what drums/hubs?
Anything that could miss matched that is letting the wheel flex in that situation ? Reverse wheels with a lot of offset?

 

Swap out that old front end for an independent Mustang II style suspension and you won't have any more of those issues.... LOL. But seriously, I would check the bore on those kingpins. I've installed new bushing and new kingpins before. got the death wobble. Started over, careful to install the correct shims and had no issues. Also, a big fan of making sure that axle is laid back about 7 degrees with a generous amount of tow. It'll track straight at 80mph over any bumps without the wobble.

 

Starting looking it and the tie rods ends needed some tightening. I'll go through everything else today and report back.

 

Hello,

When my wife and I purchased our 327 powered 40 Ford Sedan Delivery, we thought it was a complete car, ready to take us and our business to the next level. We could not wait to get going on our road trips to use the 40 Ford Sedan Delivery the way we wanted and have a cool hot rod at the same time.

The excitement of a 327 powered sedan delivery was so great that somehow we overlooked the driving/handling aspect of the hot rod. The paint was red… not like my teenage sedan delivery that was previously painted a “Salmon Pink.” So, that red color was the attractive thing at first sight. The drive around the industrial area was good as it was stop and go normal city traffic. We did not get on the freeway nearby and drove around several blocks. It was good for us.

Little did I know that on the way home, I would drive the 327 powered sedan delivery home on the freeway and then things started happening. The front end rolled smoothly until around 50, then started wobbling slightly. Then at 60, almost disappeared. When I had to apply the brakes, the pedal push almost went to the floor. I had to press with all of my foot power to get it to come to a complete stop, once I got off of the freeway.

Now, I was having second thoughts, but a cash sale was not going to get reversed anytime soon. It was ours to keep or sell. When we got home, my wife and I took a short ride down PCH and absorbed being in the nice interior bucket seats. It started again like your problem. It was not so violent, (like my brother’s Jeep FC that made us drive slow speeds until we sold it.) But, it was enough to notice and not like it.

The fun feel we got, over rode the safety issues that were noticeable to me, but my wife just liked the action of a nice looking powerful hot rod. It certainly was a step above her 62 Corvair for looks and coolness. She did not notice the ill handling situation. Although it was there. We thought we thought it was a part of old cars

When we got back, we talked about the hot rod sedan delivery with its plusses and minus points. We came to the conclusion that the cost to repair and replace parts was good for us and the future of the cool 40 Ford Sedan Delivery as our family hot rod.

Jnaki

Luckily, after everything I did to get it to handle correctly, we needed professional help. The experienced guy that we had gone to in West Los Angeles for all of our hot rod/cruising sedans front end suspension and alignment needs since the beginning moved near us in Orange County. So, it was a natural to go see him.

He drove the car and we went on all surface, local streets, flat industrial areas, and on the freeways. Then he laid out a plan. He said the tires were terrible and so I bought 4 new tires. He sent me to his friend with a tire shaving place nearby. I had all tires shaved and came back to the shop. When I looked at the amount of rubber on the floor near the shaver, I was totally amazed. There goes several hundred miles of road trips in a few minutes of circular motion on the machine.

When we got back, my friend started to take apart almost everything. So, the plan was to repair what was fairly good, replace the bent or out of whack parts and install new components. The front end looked empty when everything was taken apart. He installed new shocks, steering arms and other long rods underneath. The new brake pads, turned the rims and when it was all finished, almost everything was new and balanced.

The steel rims + new shaved tires were given a bubble balance, then spun on a machine and installed. The whole front end was given the old and new alignment treatment and everything was ready for the test. With all that was done, he said I did not need sway bars or other suspension mods. Just a good balance and alignment with the new stuff and it drove like a real car. Stopped on a dime, turned corners without much lift or grab, and on the freeway speeds, it was a no hands straight ahead acceleration. On the freeway down a mile or two, he let go of the steering wheel and it drove itself straight ahead.

Note: When I drove it, I could feel the road with the new tires and nothing was shaking. The no hands on the wheel was amazing. Stopping was instant and would have to get used to actually having stopping power. Now, the looks and handling went along with a cool hot rod and I could not get my wife out of the driver’s seat. She loved to drive it to her friend’s houses for visits and it, too surprised those wide eye looks.

When we drove to family events, no one had a hot rod and when a red 40 Ford Sedan Delivery came rolling up, they all glanced at us and wondered if we had gone crazy. The cool A/C kept us in a good way in hot inland OC and we even drove it to my wife’s brother’s wedding as I was a freelance photographer to add to the series of photos. But, the looks we got in the parking lot said it all… YRMV

Note 2: See a good front end alignment guy and get those new tires shaved/balanced and check all suspension components. Not worth the effort unless you are willing to spend some money to get it right. It is/was worth every new component and yes, a little more money than we could afford. But, it came back in droves with the access to other customers and photo stories along the way…

 

I couldn't agree more. My 1999 Jeep Cherokee has a dampener from the factory, I guess they must've got it wrong when it was engineered.

 

Your '99 Cherokee has a stock '28 Ford front end with tube shocks?

 

Kerry, Can you expound a bit for those of us willing to learn? Sounds like you mention multiple geometries here. The OP found he had 4 degrees or so of caster. That's too much in a light car? And with too much (positive) scrub radius does he need to have the axle bent, go to larger tires, etc? I also assume you mean by shackle angle that the wishbones weren't pie cut to give the proper caster angle?
Tman mentioned a tapered shim for more caster but does that do anything if the bones are not also effectively lengthened?
Lot's to take in here.
D

 

Calm down boomer we don’t want you getting over excited this close to bed time .
I said not really a fix , didn’t say steering dampers were useless just that it’s not going to fix the underlying problem , your right in many situations a damper will help and improve ride qualifier but it’s not going to fix a death wobble problem , that’s clearly a bigger underlying issue .

 

A few pics of your front end,can often help others see,something that seems OK to you,but is off the mark,so can add to a prob. The info from that can help

 

Back to basics, Measure the wheelbase on each side of the car. It should be the same

 

Yesterday I had some time to look into it. The early ball & pin style tie-rod ends and drag link needed to be tightened. I guess the springs loosened up since being installed.

King pins and wheel bearings are all tight. I will check alignment and wishbone mounting.

I'll get some pictures as well.