Sudden low speed front end wobble / waddle

[Lady72nRob71]

Well, if it's not one thing, its another...

On July 4th, a ladyfriend and I took my 72 Cutlass to the lake to watch fireworks. All went well on the way down there (80 miles). We hung out at the marina's waterside restaurant and had a great time.

On the way to another unofficial show, I suddenly noticed a sudden, sickening wobble in the front end as I was slowing down to about 35mph for a light. I figured it was the new asphalt, but no, it was persistant. It was like someone was rocking the front from side to side. There are no other symptoms, like clunks, pops, bad handling, or anything to indicate a failed suspension part.
She still drives straight and stops straight.

After that last big fireworks display at 1am, twenty miles later, we stopped at a gas station and I looked at the tires... The front right tire has bad feathering on the outer edge, possibly from misalignment after the upper control arm bolt breakage 3 months ago.
The wobble is noticable from 5 - 40 miles per hour and can be felt a little above 65. Cruising at 55-60 was okay.

The service manual called this condition "waddling" and said it is often caused by the radial tire's internal belts separating. My tires are old but still look nice. I do not know how old, except they are stamped "made in USA", which means they must be pretty old...

Any ideas or experiences on this before I go swapping tires around?

[gearheads78]

Sounds like a separated belt in a tire. Thats about the only thing that will do what you describe all of the sudden.

[Texascarnut]

That does sound like a thrown belt on one of the front tires. Best way to get a handle on it if not visibly obvious is to jack up the front end and give the wheels a spin while holding your hand against the tire. If there is a bad belt you'll feel it as the wheel rotates.

If any of those radials are over five years age (they do have date codes) they should be replaced........Not safe at highway speeds, period!

Your mention of noticeable "feathering" would certainly indicate severe alignment problems, which can indeed lead to belt sifting if the tire is darn near laying on its side. Definitely an unsafe circumstance.

[Lady72nRob71]

Originally Posted by Texascarnut

jack up the front end and give the wheels a spin while holding your hand against the tire. If there is a bad belt you'll feel it as the wheel rotates.

Thats an easy test - I will do that one first...

Originally Posted by Texascarnut

(they do have date codes)

Where are they and how are they deciphered (if not obvious)?
I am curious...

Originally Posted by Texascarnut

Your mention of noticeable "feathering" would certainly indicate severe alignment problems, which can indeed lead to belt sifting if the tire is darn near laying on its side.

Looking at the tires from the front do not show an obvious camber issue, but it could very well be off from the previous suspension issue.

[Texascarnut]

Rather than trying to briefly explain the where and how to decipher the date codes, you'll find illustrated information here:

http://www.tirerack.com/tires/tirete....jsp?techid=11

There are people that will argue about the 5 year thing, but that recommendation is from the U.S. DOT. We've all perhaps foolishly ran tires older than that on our vintage cars but that doesn't make it a good idea. I would be more prone to saying aging radials are more likely a problem than aging BIAS Ply tires, simply because the sidewalls on radials are not nearly as strong/rigid as those on BIAS Ply tires and the constant flexing makes for greater failure potential.

If the front end wasn't aligned after the issue with the control arm bolt that may be the source of the problem. But as we all eventually figure out aging suspension parts and bushings can cause unexpected issues.

I've come to realize after years of buying vintage cars the first thing, as well as often least expensive thing in the long run, one should do is just replace nearly the whole darn suspension and steering before some sort failure leads to having an accident or causes damage and failure in other components. I've yet to buy a car over 25 years old with a front end in truly road worthy condition, though often the seller will proclaim the car can be driven anywhere. Yeah, maybe on a trailer or on the back of a rollback wrecker.

[citcapp]

X2 on the 5 year tire age. UV rays take there toll on tires. All tire manufactures recommend 5-7 years and they base it on how you store your car. Direct sun light and they degrade faster, stored out of sun light and off on dirt and they last longer. I have been a motor home owner for 30 years and have seen more the one accident caused by old tires comming apart on the road.

[BIGJERR]

I would swap front to back if possible and see if it still does it...........Or a complete diffrent set of rims and tires.........If it goes away its a tire issue...............Jer