New 'Death Wobble'

[Canton_Model_A's]

Good day to all here at the barn. I have a question that hopefully can be answered.

A year or so ago, I had the infamous 'Death Wobble' in my 'A'. I proceeded to install new King Pins, Bushings, etc. That resolved the major Wobble. Now recently it has returned. I am assuming this has to do now with the steering. My steering wheel has about 1-2" of 'Play' in it before it starts actually turning the car.

My question now is; what could be causing the wobble this time. I do not know the age of the steering gear, I believe I have a 7-Tooth steering box (haven't confirmed it yet). Should I plan on redoing the steering gear next? Oh and I have checked all the lugs they are tight, and when I did the king pins I repacked the front bearings.

Thanks y'all

Dave

[nkaminar]

Dave, The wobble can be coming from a number of different places. The steering box is one but first check to see if the ball at the end of the wishbone is tight. Also where the wishbone fastens to the front axle. Also check all the ends of the drag link and tie rods. Check to see if the pitman arm is tight on the end of the steering box. Check the toe in.

To some extent the 7 tooth box can be tightened up. The 2 tooth box has more adjustment. Try adjusting your steering box before tearing into it.

Do you have the Red Book, https://www.snydersantiqueauto.com/p...031&cat=41621? It has some great instructions on how to identify and how to adjust and repair the steering components, including the box.

[rotorwrench]

Steering control feedback can come from looseness in the controls or from damaged tires. If there is a tread separation in any of the tire carcasses it will be problematic. I jack each tire off the ground and feel for unusual bulges in the carcass. It can happen with the tread or the side walls. If I suspect a tire, I remove it and roll it on a nice flat surface. A bad tire will not roll properly. They tend to wobble and fall over no matter how straight they are guided.

[johnbuckley]

Shimmy/wobble can be caused pretty much by anything between the front tires and the steering wheel: balance, wheel bearings, kingpins, axle, tie rod ends, drag link ends , drop arm , steering box. It often case of checking /tightening things until it goes away.... (PS IMHO just 1-2 inch of steering wheel play is very good for a Model A that's used and not sitting in a museum!)

[Canton_Model_A's]

Yes I have the 'Bible' will go thru things.

@RotorWrench, brand new tires this year, 5x Good Year Balloon 21.5" Tires

@John Buckley, will go thru the front end.

I do appreciate all the responses here.

Dave

[Tacoma Bob]

Sponsored Links (Register now to hide all advertisements)

I chased this demon for some time. I replaced everything and more. At the end of the day it was the nuts on the end of the front spring perches. If they are loose the axle will wobble. Once I tightened them ....no more death wobble. P.S. you may need a cheater bar on your wrench as they need to be very tight.

[Marshall V. Daut]

Following up on what Tacoma Bob has written, it helps if you heat those perch nuts with an acetylene torch. You'd be surprised how much you can tighten up those nuts when they're close to being red hot, maybe two or three castle nut gaps, even more sometimes. This is one aspect of front restoration a lot of guys either don't know about or decide it's not worth the effort. I heat and tighten those spindle nuts on every front end I rebuild. I learned about this issue the same way Tacoma Bob did - by a long, fruitless chasing through all other suspects until it occurred to me to check the spindle nuts. To my surprise, after heating each one I was able to turn the nuts almost a 1/3 revolution tighter. And like Bob's experience, that solved the death wobble, whose cause had been so elusive and frustrating to pinpoint. Fixing the problem once it was uncovered was a piece of cake. It was GETTING that point that made me want to pull out my hair. Fortunately, I didn't do so.
Marshall
ADDED - By the way, if you do heat the perch nuts, leave the front spring in place, or at least the main leaf. Otherwise, you run the risk of twisting the spindles in their bores, causing misalignment across the spring. Keeping the spring attached to the spindles via the shackles (spring hangers) will stop the spindles from turning. Use a 1/2" drive breaker bar with the appropriate size socket, not a puny 3/8" drive. Even better, use a pneumatic ratchet.

[old ugly]

i chased an issues same as this. on a car that had all new and tight parts. the cure i found is to tighten the drag ling and tie rod end caps tighter than what the books say.

i think what was happening was a bounce back and forth from one spring end to the other.

it is an easy thing to try.

[Wick]

Check the front spring.....is it old and flat? This will cause the death wobble also, look for cracks in the front crossmember.
To remove a spring perch use a big air hammer that's used for concrete. Knocks them right out!!

[rotorwrench]

The OEM front end has several points where the fit up of joints was such that it required springs to add the needed tension to keep the joints tight. This was old technology so it can sometimes become problematic. Tie rod and drag link sockets are all this way and the major item is the is the radius rod 1.5-inch ball socket on the back. Make sure they are all in good shape. I'm not a fan of the rubber ball type alteration for those. They work better if they are original design but they do wear out. The radius rod to perch set up used tapers to tighten it up so the nuts have to be tight. When I first purchased my 29 Sport Coupe, I found that a previous owner had welded the front of the radius rod yokes to the axle due to loose fit. I had to replace the front axle, the spring perches, and the radius rod due to that.

[spdway1]

Alignment, follow Paul Shinns' video covering this. The actual process takes about 15 minutes. I find this to be 90% of the problem helping others out.

[ModelA29]

Our Tudor has a wobble - it's more of a slow hula wobble rather than a full on belly dancer wobble. I tightened a very loose wheel bearing and that helped about 70%. There is a little slop in the steering and a hard left on the wheel will stop the wobble before it gets going too bad. My king pins seem tight so I'm going to start looking for play in the box and all the steering connections.

[bruceincam]

Originally Posted by old ugly

i chased an issues same as this. on a car that had all new and tight parts. the cure i found is to tighten the drag ling and tie rod end caps tighter than what the books say.

i think what was happening was a bounce back and forth from one spring end to the other.

it is an easy thing to try.

How much tighter? Half a turn; full turn?

[philosofriend]

Originally Posted by bruceincam

How much tighter? Half a turn; full turn?

Have someone turn the steering wheel back and forth while the wheels are on the ground and your hand is on both parts of the linkage. You will be able to feel any looseness in the joint even if you can't see it. Tighten the plug until you can't feel any slop. If you are tightening and you feel a sudden increase in effort to turn the plug, then you have fully compressed the spring, don't drive it like that, the spring will break. If you can't get the slop out you need to make the ball round again. I suspect that the plastic seats in the EZ steer kit can deal slightly better with a worn ball.

[Big hammer]

I bought a used modern from extended family, took it for a short drive in town, came back and said I’ll take it . They asked are you sure, me yes a need it for better gas mileage. On my way home I got it up to highway speed and OMG death wobble BAD !!!! Got home by staying under 40 mph. Took it to an alignment shop, they found a bent wheel on the front, move it to the rear and has good to drive.

[Robert/Texas]

I would go with what Big Hammer said. I had a 1927 Touring with original wire wheels which looked much Model A wheels. Every once in a while, when I hit a bump, I would get the death wobble. I replaced the kingpins and worked on everything else to no avail. One day I decided to reverse the front and back wheels, and the problem went away.