Technical The search for a cure-Death Wobble SOLVED!

See below.

 

Gotta speel it right "Deth Wobbel" . We cherish our history here on the HAMB

stell got my deth wobbel | The H.A.M.B. (jalopyjournal.com)

 

I had this long diatribe typed out and it won't accept it from my phone......ugh.

 

The facts:

1935 Ford pickup with sbc

Radial tires running 30 psi

The front spring is a Posies reversed eye

Shocks are tubular Chassis Engineering.

Toe in is set at 1/8”

The caster angle is 8 degrees

Wish Bones are spilt mounted on the X member.

The steering box was a Saginaw 525 purchased used from a fellow hamber 20 years ago.

The tie rods ends are all new and tight.

The truck has a steering dampener.

One of things I am most suspect of was the steering box and the mounting plate. When I first installed the plate, the instructions from Pete and Jakes had been copied 150,000 times and were illegible, so I do what most guys do…..wing it. This lead to me omitting one bolt, due to the fact that I Didn’t know you were supposed to oversize the hole in steering box, since the instructions were so bad. If you saw it, a few weeks back I asked about an article Pat Ganahl did back in 1975. You can see that here.
https://www.jalopyjournal.com/forum/threads/help-me-find-this-article.1263650/

I ordered a new Borgeson 525 box and started the install. I noticed that the box had some movement in it, since all of the mounting had backed off. This surely has an impact. That’s the first thing.

The second thing I was curious about was the box itself. I seemed tight but under a load, I could see a deflection in the sector shaft. Not much, but it all adds up.

The third thing was the gap between the I beam axle and the wishbones. I spoke with the tech guys at Pete and Jakes and they said that Ford never came with a shim, but they had them in stock and they were cheap. So, I ordered a set.

Now this truck has always rode like total butt. It is harsh and makes me consider a non-traditional suspension option. I want to remedy that. I hear guys saying my 40 rides like a Caddy. Well, I want to be that guy, so I am venturing into this with an open mind.

I’ll add some pics as I go along

 

Sometimes I think our devices do us a favor by deleting what we think we want to say.

 

Here is a pic of the gap between the axle and the wishbone. I don’t know if this will make any difference, but it make me feel better anyway.
This is a before and after.

 

Something else I found was that the shock brackets were loose on both sides. They were both mounted with nylock nuts and shouldn’t have backed off. I went ahead and sprung for the Bilstein hot rod shocks. These are really nice. They look too nice for my truck.

 

You'll like those shocks, I have them on my roadster and my PU. I like the shim idea, tighter is better (not engine bearings so much).

 

You mentioned your car does not ride good. Ride has a lot to do with spring rate. That’s usually why a truck does not ride as good as a car. But one thing about leaf springs is that they slide against each other! Some have little pockets to place a “ pad” to reduce the friction to make them work easier. Unfortunately leaf springs can get rusted almost together so that the hardly work! Might want to check your springs for rate and ability to flex!
I will share a story about my Dad right after the depression era when these cars were everywhere. The roads here around the ranch where terrible, so to make the vehicles ride better he would Jack up the car/trucks and put a nail in between each leaf, to act like a roller! He said the vehicle road like a dream…. until the nail either fell out or wore out! Now I do not recommend this, just things that happened in the past!






Bones

 

What was the caster angle on the truck? What was the shackle angle? How much toe in?

 

Root could paint the truck gloss black and call it Darth Wobble. "I feel a tremor in the truck"

 

Tman, I went back and read some of the posts on that thread, Wow! That poor guy didn’t last two months!
That reminded me of my first post, I didn’t read the rules all the way through and promptly got jumped on by several guys! I though…wow these guys here are tough!
But I went back and reread the rules, reworded my post and didn’t get butt hurt!
You need thick skin to hang out , here! Lol




Bones

 

When looking for help,lot of times a few photo's of views around the frontend are good.
At times we over look what is right in front of us,in someway!
A lot of things can add too wobble,but it only takes one trigger thing to start it off.
Often a combo of missed little stuff can add up.
My little speed shop before I retired,was the place to bring ride prob's too ,among other stuff other shops could not or didn't want to deal with. Lets see some pics.

 

Hey Root, give me a call and maybe I can help. I've done a few 40's. 731-608-9010

 

Thus us beeutifal.

 

The toe in is set at roughly 1/16”-1/8” depending on the cheesy tape measure I choose. Of course, I don’t have a very good measuring tool. I need to invest in a real one.

The caster is 8*.

The shackle angle is hard to tell because it’s one of those Rube Goldberg CE triangle deals that rotates. I haven’t measured it yet.

 

Thanks. I am at the office , but when I get to the house I’ll try and give you a call.

 

@Roothawg , don't remember if we talked tire pressure on the phone? What are you running? Too high and you will get the "superball effect" . Couple that with some of your other issues shown and you prob have it licked.

 

Yeah, I have radials on it. I lowered the pressure to 30 psi. That’s about as low as I am comfortable running them.

I had a lot more info on this thread, but it only pasted over about 80%.

 

"Deth Wobbel" troubleshoot 101:
First, with the jack under one end of the front axle raise up the vehicle until the tire just barely clears the ground, then spin the wheel to see if the tire is out-of-round or has a bubble from a bad belt. Now spin the wheel to see if the rim is bent. Try swapping out both front wheels with some that are known good and go for a drive.

After that raise the vehicle up so you can get a hand under the tire, then with a hand on the top and bottom of the tire pull out/push in to test wheel bearings and spindle bushings.

Next, with a friend holding the steering wheel as tight as they can, you, with a hand on the front/rear of the wheel, pull out/ push in to test tie rod ends and steering boxes. It helps to have friends watch those steering components for relative movement while you yank and pull.

Does the vehicle have a panhard bar? Without one, if "Deth Wobbel" starts the whole front axle can move from side to side. Best of luck with your project.

 

Too high. I ran the Rocky33 at 25

 

Yeah, but you’re a rebel….

 

Root, I know your a good Fabricator. The “ go to” alignment shop here in Muskogee used a square tubing and two movable uprights , secured with a thumb screw. Very simple and easy to make! They also had a little spring loaded scribe that they put a mark near the center of the tire , as it spun. They would just put it in the front and rear of the tire to measure toe in!
This method takes in consideration for a little tire run out, that they all have!

I have never built one, due to not that much need , but I have spun the tire and used my knife on a block to scribe the tire and the measure with a tape! Works most of the time, but the square tubing and uprights gets the measurement near the center of the height of the tire, which is important!





Bones

 

I agree, but don’t it will cause the wobble. You won’t regret a call with Dale.

 

Been there, done that. Death wobble is the deflection of one wheel (like from hitting a bump) being transferred WITH A DELAY to the other wheel...and then back again in response - with a delay once again. This delay sets up an oscillation we know as death wobble. So look for loose stuff that would allow one wheel to move while the other other one stays still. This would include under-built components flexing as well as the normal loose nuts and worn king pins. Good luck!

 

It will, with too high of pressure couple with his loose front end parts it will start a superball like oscillation that can start going front one side to the other getting more violent until you drive through it or back off.

 

You agree with Trent or me?

 

we posted at the same time!

 

read the hole post thuw that theirs sum funny shit!

 

I ran as high as 34 psi in the radials in my 32 and never had problems. Mine was a C.E. forged axle, needle bearing king pins, C.E. spring like a Posies, hairpin radius rods, panhard rod and 7 degrees caster with a 1/16" toe in. I used a Unisteer rack and pinion. It was all new when assembled and had almost 40,000 miles on it when sold.