"Death Wobble" in '67 a-body - think it is FIXED!

I have a completely rebuilt '67 barracuda. Ever since I put it together it always had an odd shimmy in the front end. It was never that bad, just something that I could never figure out. It would come and go randomly.

The car is "completely new", full rotisserie restoration, almost every part touched.

Setup:
1. manual steering, I installed and setup myself the 20:1 quick ratio gear box.
2. All new Moog (US) front end components
3. '73 (used, but restored) front disk brakes (and the 10.5" rear drums for big bolt pattern on the back).
4. Alignment done by me with a fasttracks unit. Aligned for maximum caster, I can't remember where I set the camber (1 deg?), and the toe at 1/16 (I think).
5. new rubber LCA bushing, Moog Rubber "problem solver" rubber bushings in the UCA (2x in each in opposing directions)

Car drives straight, but does have a lot of slop in the steering wheel (at least from 11 o'clock to 1 o'clock). Overall it handles well.

Sometimes if feels like the front end is moving to the right and left a little bit in some set frequency, moving faster you can "push through it" and then it stabilizes out.

I drove the car today, and it appeared a little worse, but it has been a while from the last time I drove it, so I don't know.

Anyway, I hit a large pot hole on the right side and it entered into what can best be described as the "death wobble" I see on the Jeeps, a violent back an forth on the steering wheel, but still tracked straight.

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This is what found and it drives MUCH better!

Well I think I found out what it was... Should have been the first thing I should have checked!!!

The wheels were toed OUT, only slightly but but about a 1/16-1/8.

I toed them back in and it is MUCH better, need to get a real alignment now!

The steering box was definitely loose, which was a factor, or maybe a symptom, and it might never have been completely tight.

Pulled over, checked that everything was tight, tie rods are tight, upper lower ball joints appear tight (still on cotter pins), UCA bolts, LCA bolt, etc. Steering box appears tight to k-frame.

Everything in the suspension appears tight; limped it home, with no major issues, just some occasional left right osculation in the front end.

Any thought of what to look for?

Idler arm, worse set-up on a 67 as it doesn't sandwich between two pieces of metal, a through bolt holds it on at one side. I had it once in my 69 Dart 383 and it was the idler arm. Even if you have a new one on it there still could be issues with it especially with parts made today.

On alignment, in general, positive caster and negative toe (toe in) promote stability. More of both would be better if you can get it. 1/8" - 3/16" toe in and up to 5 degrees caster.

Still it should not wobble like that. Worth checking for something loose in the steering mechanism IMO.

Check the tubes in k bar for broken welds. I’ve had those on cars I’ve redone. Fixed before driving, so no idea if it would cause your issue.

What is going on with box? You rebuilt it and it isn’t tighter than that? Adjustment maybe? Problem with coupler?

Might be hard to do on the ground (ramps? or if you have access to a lift) but you might have someone "wiggle" the wheel between the 11 and 1 you mentioned and see if the linkage is moving up and down. If not, I would tighten the box up some.



Tim

Slop between 11 and 1 sounds like a steering gear box adjustment issue.

As said, checkout/correct the box first (start with the coupler/shoes). then a good visual/checkout elsewhere since as you know something is loose/misadjusted/bad. Holler how it turns out/what it was.

Plan on throwing it on the lift this weekend. Just wanted some ideas, as on the surface (other than the box), everything appears OK.

I'd like a better description of the wheels and tires as well as balance method.

Don't overlook the rear suspension

The car has cragger unilug 15" with Cooper Cobra tires. Like a 225/60 or 65? On the front.

Had the tires ballaced when the tires were put on. Spinning ballancer

I have dealt with this on 4 wheel drives that had otherwise good suspension- bushings, tie rods, etc. The oscilating you describe, particularly after hitting a pot hole on one side is exactly what one of my trucks would do and you are correct- there is no driving through it.

Check the tightness of the wheel bearings- I know it sounds different or weird but I had just rebuilt my front end, just like you, and sometimes with all that fresh grease etc., you need to go back and retighten. I have a tendency from my drag racing days to set stuff up too loose.

I did that and the truck was perfect.

Try adjusting the centering valve in the steering box that did wonder for my old Plymouth with a ton of free play now minimal

Follow the procedure in the FSM.

The centering valve is only in a power steering box, right? I think he said it has a manual box. It sounds to me like your steering box isn't set up right. I would check the idler arm as already suggested, but I would also disconnect the drag link from the pitman arm and make sure the box is set up right. Count the number of steering wheel turns from one extreme to the other. Turn the wheel back exactly half way. This will be the tightest position of the steering box (least clearance). The adjustment for this clearance is on top of the box, there is a jamb nut and adjusting screw. Adjust it until the clearance is just about zero. This should also be the position where you center the steering wheel, too. You may have to adjust your tie rod sleeves to straighten up the front wheels after you re-connect the drag link. I would also make sure you don't somehow have a lot of negative caster. If everything is good and you still have an issue, try changing to another pair of front tires just to rule them out.

My hemi dart would go into the death wobble sometimes. couldn't figure it out at first. nothing damaged, went on alignment rack a few times.

I couldn't figure it out until it happened really bad, then when pulling into the driveway my oil pan scraped the ground where it never had before. the front end was riding lower. if you watch a drag car do a big wheel stand, when it comes down hard the front end shakes for second before the suspension recovers and lifts the car. in my case the torsion bars were weak and wouldn't lift the car out of it. If I hit a bump or on hard deceleration it would go into the shake.

This goes against normal thinking as it is a scary situation, but if it happens again hit the gas for a second and see if it lifts out of the shake. might want to check your ride height, and that your torsion bars still have enough spring in them to snap the car back up to its proper ride height.

might be a different issue in your case, but that is what I was up against.

i did some front end work at my brothers house once and we eyeballed the toe. it was toed in a bit too much, it would do what is described in the original post. at certain speeds if i hit a long bump that would really oscillate the suspension, it would really turn into a handful.
got it aligned and i never noticed it again.

All it takes is a few scraps of metal and a welder to correct that. Did it on both of the 66-67 I used to own.

Well I had a chance to get it on the lift, think this might have been a factor...


All three bolts finger tight, and one completely loose...

There ya go!!

tried to post a pic, but even after resizing it on the phone, still too big. I which they would just allow any size pic to be uploaded and then resize it on the server....

Keep cropping until it's small enough.

Glad you found the issue.

3 bolts on the...steering box was loose? Good thing you found it; potentially dangerous.

Well, still not it...

figured that was the smoking gun... but not, ended up taking it around the block (for the first time), and it is still there. Steering appears much tighter, but still has the wabble.

It has unilug cragars on it, so I pulled them off, checked everything (suspension wise) and it appears tight (on the lift). I removed the wheels and was careful in putting the unilugs back on, but still the same issue.

Checked the runout on the rotors <0.001" bearings appear tight, rims are straight (by the rotate eyeball method), no bulges in the tire in the sidewall or tread (again by the rotate eyeball method).

I do have another set of rims/tires I could put on the front (again unilugs), but might try that to debug.

At a lost and getting extremely frustrated (with this an everything else)...

I think you are going to be a happy man real soon.

I'd try another set of rims. I bought a brand new set of unilug Cragars in the 90's and it never drove right. Tried everything, balancing, rotating, etc.
Finally figured out they weren't true.
It's the rims

for what it's worth. FSM's of the era state maximum runout where the bead seats as : radial runout [up and down] - .035, lateral runout [side to side] - .045. with tire mounted : radial runout [measured at the center of the tread] - .080, lateral runout [measured at the sidewall] - .105.
sometimes it is necessary to rotate the tire on the rim to get the best results because the tire and rim both may pass standards, but when mated, are way off.

BUMPSTEER! Jack the car up until wheels are off the ground and measure toe-in and toe-out.one wheel can be towed in while the other is toe-out.then loosen t-bars and lower the car all the way down and measure toe.I bet you will find your problem.The old mopar chassie book will tell you how to fix.

What does John say? Want me to come over and take a look?

I had the welds break on that piece where the lower control bolts into the k-frame years back and acted like what you have going on

IDK, did not look at it tonight, tried to get the '73 ready to try to take it to Milford Friday.

John was thinking something in the tire (belt or something), but I don't see anything.

I don't think it is bump steer issue as it is an all original suspension / parts and it has the "wabble" on a flat road.

As far as welds breaking, this could still be a factor, but in my inspection it does not appear to be the case (I have not seen anything, but, eyes are only so good). Yes, it is a 67 (weak) k-frame, but this happens on just driving straight, no "performance" driving, I assume (maybe falsely) that all '67 a-bodies did not wander all over the road going straight on smooth level roads?

No you are right, as we know there is something going on. I cant wait to find out what it is.

Did you check the pitman and idler arms. I had a pitman totally break in half. Turns out it was cracked and the idler as well. Bought a new pitman and idler. They too had hairline cracks. Went through several sets before finding clean parts.

That would be crazy! I looked at them, but honestly I don't think I would have seen a hair line crack.

It is the orig pitman arm, with a NOS Moog idler arm (hard to find part for a '67).

Today's mini update...

Put a different set of rims/tires on. They were unilug aluminum slots, but they have recesses for the unilug washers. I thought I had a set of steel rims / tires, but they are small bolt (and this is big bolt).

Now, I am checking (as best as I can) the alignment / toe with the fastracks... Well see what I find...???

Too bad you are not closer! I have all sorts of rally and other wheels you could try. I have stuff I may never use.

Well I think I found out what it was... Should have been the first thing I should have checked!!!

The wheels were toed OUT, only slightly but but about a 1/16-1/8.

I toed them back in and it is MUCH better, need to get a real alignment now!

The steering box was definitely loose, which was a factor, or maybe a symptom, and it might never have been completely tight.

Toe out, I never woulda thought!

Don’t feel bad, I had this annoying front end thunk that I chased for a year. Changed lower ball joint, lower control arm bushing. No change! Finally got the wife in the car to turn the wheel a little back and forth while I watched. Out of the corner of my eye I see the k frame move just a hair. All four bolts had back off to finger tight! Doh! I remember thinking when I tightened them the first time “These are forty year old rusty threads that would be a diaster if you strip them!” This time, IMPACT!