I've got a '66 122 that I just replaced the front suspension bushings and ball joints on and now at speeds around 35mph I get VIOLENT shaking of the car (almost as if the tires are barely attached to the car). I went through and made sure all the nuts and bolts that were involved in the process were up to spec and the lower control arm long bolt on both sides of the car was a little loose. So I tightened it to 110 ft-lbs per the vclassics bushing replacement tech article and took it for a test spin in the neighborhood. All seemed fine up to ~40mph and then I hit a small bump in the road and the shaking commenced (not as violently as before, but still bad). My tires are badly worn, biased towards the inside, and my guess is the tires got bad because there wasn't really much left of the old bushings I was replacing.

So my question is did I mess something up in my replacement that's causing the wobble, or now that the bushings and ball joints are new, the tires' wobble is more pronounced (not that there was any noticeable wobble before the procedure)?

Logically, I think it's something I did because it seemed fine before I tampered with it, but is it possible the next weakest link is making itself known?

Thanks for the help.
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Andy - '66 122s, '79 264

ok I know from experience that worn out bushings tie rods etc will hide bad tires as all the slop hides the tire wobble. That being said from the tire wear, you need to do an alignment, from my experience you can do this yourself and get acceptable results. Surprised everyone is saying take it to the shop, the manual has clear instructions that will allow you to get it "pretty close" yourself on a flat surface. Worrying about caster camber before you have checked the toe in is useless. It is fairly usual for a newbie to mess up toe in when changing tie rods etc.... I don't find the 120 very fussy, has a tiny bit of toe in if I recall correctly check the book good luck.

I have to disagree with a couple of points here, Patrick. :)

First, while doing a quick and dirty DYI alignment may get you by, unless you have a good caster-camber gauge and some experience aligning front ends, it's almost certain you'll end up in an alignment shop anyway. That is, if you care at all about how the car drives and how long your front tires last.

Also, if you're going to be adjusting camber at all, you do the toe-in measurement/adjustment last. That's because camber adjustments can have significant effect on your carefully adjusted toe-in. Conversely, adjusting toe-in has no effect whatsoever on camber and caster settings. Ergo, toe-in is the last thing you adjust, not the first.
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Gary L - 142E ITB race car, 73 1800ES
YouTube Racing Videos

quiet agree with you on your points, and was not suggesting he DYI his caster/camber. My post also agrees with you, so while toe in is last to set it is first to check, especially if nothing has been changed re caster/camber. Basically if he changed tie rods etc, he can quicky check the toe in, or even just screw it in a little, toe out= vibration wobble, toe in = tire wear etc..

p.s. tire shops have bent my rims and caused problems as well....watch out the older style tire changer that just grabs the center hub can bend the center hub. "newer" ones hold the wheel by the rim for removing the tire, haven't seen the old style for awhile but i'm sure they are still out there.

You didn't mention whether you had the front end aligned after replacing all those parts. If you didn't, do so. If you did, do so again. :) This sounds like a classic case of "caster wobble", caused by excessive negative caster. The green book says caster should be 0 to +1 degree. I personally like even more positive caster, despite the fact it can make low speed steering a little stiffer. In any case, you certainly don't want negative caster.
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Gary L - 142E ITB race car, 73 1800ES
YouTube Racing Videos

I did not get the alignment done, and I guess that should be first on my list. Thanks.
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Andy - '66 122s, '79 264

+1 to getting the alignment done. That should always be done after replacing any joint in the front end.
Both of those tyres are seriously past their usage date and show signs of toe OUT wear. Dangerous when braking in the wet. Wobble might have been disguised while there was so much wear in the suspension.
Check the flexible joint in the steering column. Replace if showing any signs of twist movement or distortion.
Get your wheels balanced but best done after you've fitted new tyres. As said, fitting the rears on the front might help with the diagnosis unless they are in the same state as the fronts.
Pictures look OK but check all of the steering arms and joints along with the idler bush.
Did you tighten the A arm nuts and bolts with the full weight on the car suspension? I assume you replaced the upper inner bushes? Those are the first to wear and don't last long now days but are easy to replace with poly to good effect.

Yeah, alignment is first on my list (followed by tires).

The steering coupler was replaced a couple years ago and is holding up fine.

I did replace the upper inner bushings with poly ones as well, and they were actually in better shape than the lower arm bushings. In fact there wasn't really much of the rubber of the lower bushings left when I pulled the lower arm off.

Initially I tightened the lower arm nuts and bolts with it unloaded, but then tightened it again after the first vibration incident because I thought it may have been loose and causing the problem. Is that a problem?

The Idler Bushing shows cracking in the rubber, but there is no play in the bushing from trying to shake it by hand.

Thanks.
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Andy - '66 122s, '79 264

Andy M said---"The Idler Bushing shows cracking in the rubber, but there is no play in the bushing from trying to shake it by hand."
Play on the idler arm will show when you rock the r/s front tire side to side. A bad bushing will cause the idler arm to move up and down. I think a bad idler arm bushing combined with obviously out of balance tires (given the wear--how could they possibly be in balance?) can result in the out of control shaking you are experiencing. Some front end designs are prone to that kind of shaking---ask any original VW Beetle or Bus driver with a bad steering damper. A 120 Volvo isn't that sensitive so I'd look for a combination of ills. -- Dave

So it sounds like my first order of business should be to move the far less worn rear tires to the front and the worn ones to the back, then take it for a test drive to the nearest tire shop with the proper tires in stock. Then if the problem persists take it to get the system aligned.

Thank you all for the help.
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Andy - '66 122s, '79 264

Switched the wheels from front to back last night, and what a difference that made. Safely reached 50mph on the way to the tire shop. Was told they didn't have the stock tires in, but will get them in today. Then on my way home, after about 2 miles worth of driving, as I was braking to turn onto my street, at about 20mph, I felt the slight wobble again. Nowhere near as violent as before, but still, it made itself known.

I'm thinking that the lower control arm nut is slackening off on the passenger side (coincidentally, also the side that the wobble seems to be coming from), because a couple times I drove it and then I'd try to check to see if the bolt was loose. Sure enough, I could get a couple cranks in before the torque wrench said I was at 110 ft-lbs again, driver's side was still to spec though. I'm thinking that I should replace that nut with a new stop-nut from my local hardware store and if the wobble persists after the new nut and new tires, I should proceed to getting the alignment done. Thoughts?

Thanks again for all the help.
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Andy - '66 122s, '79 264

Are you sure that the lower control arm nut is supposed to be at 110 ft-lbs? I thought it should be around 40 ft-lbs.

According to the VClassics Tech article, it was 100-130 ft-lbs. step 8 of putting it back together: http://vclassics.com/archive/bushings.htm
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Andy - '66 122s, '79 264

You are correct. Thanks.

Thoughts? My thought is this... you've got to forget the "if" part of the alignment requirement. Okay, I'll scream it - THAT CAR NEEDS TO GO TO THE ALIGNMENT SHOP. If it doesn't, it is an ironclad guarantee that as a minimum, you're going to be replacing the front tires again in short order.
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Gary L - 142E ITB race car, 73 1800ES
YouTube Racing Videos

Thanks, I do plan on getting the alignment done this weekend.

The "if" part was more-so if the wobble wasn't fixed, I'd have to immediately get the alignment done as this is my daily driver.

The new tires seemed to do the trick for the wobble (~20 miles driven so far with no violent shaking episodes) and I agree I don't want to have to replace those tires anytime soon, so a trip to the shop for an alignment is the plan.

Thanks again.
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Andy - '66 122s, '79 264

If your setup uses Nylok nuts as mine does then I'd strongly recommend new nuts throughout. I never reuse Nyloks.

Roy Olson

Had a VW beetle many years ago with the same problem, turned out to be wheel/tire balance. The mechanic grabbed the spare tires from 2 new cars put them on mine , went for a test ride and no more problem.

Andy, I just did the entire suspension n my '67 and had no problems. I don't think your tightening process for the A-arms caused any difficulties but you should just snug the A-arm bolts down with no weight on them and then tighten to specs after putting the car load on them. You should be OK but I'd replace the tires before an alignment. Aligning with those well worn tires is a waste of money.

Roy

Your description of the speed and effect sounds like "wheel tramp", which I've only experienced once, as a passenger in a kingpin-type front end 1953 Ford sedan in 1960. It would spontaneously begin at 35-40 mph on a smoothly paved road and was amazingly violent, making the steering wheel rotate back and forth and the whole front of the car jump around. A sudden swerve by the driver to the steering wheel could calm it briefly. My friend who was driving had been told the car needed kingpin bushing replacement.

I read somewhere decades ago that there is rapid dynamic wobbling of the front wheels in the left-right steering direction that at the 35-40 mph speed sets up gyroscopic precession forces that make the tire bounce up and down on the road and the effect reinforces the steering wobble in a "vicious circle" of instability, like a flag waving in the wind.

Car speed for tramp is lots slower than the 65-70 mph that purely vertical tire bounce from out-of-round or out-of-balance typically occurs at for independently suspended front wheels. Looseness in suspension and steering parts including tie rod ends is no help in avoiding tramp's onset.

Search "wheel tramp" online. This SAE paper abstract has a brief summary: http://papers.sae.org/330042/

If your rear tires are not unevenly worn, you might try them on the front to see if tire tread wear profile makes any difference.

It is possible to tighten the lug nuts in a fashion that the rims are not centered, so you might want to loosen the lug nuts and re-tighten them evenly and in a star pattern.

It would be helpful if you could post pictures of the parts you changed as they are currently installed on the car.

Maybe you installed something wrong that we could see.
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Eric

Hi Performance Automotive Service (formerly OVO or Old Volvos Only)

Torrance, CA 90502

Here are some pics (hopefully this works):

Passenger Side AFT Lower Control Arm Bushing:


Passenger Side FWD LCA Bushing:


Driver Side AFT LCA Bushing:


Driver Side Ball Joints and Sway Bar Link:


Passenger Side Ball Joints and Sway Bar Link:


and here is the wear on the tires
Driver's Side Front:


Passenger's Tire:

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Andy - '66 122s, '79 264

Also, while I did tighten the lug nuts in a star pattern initially, I'll loosen them and re-tighten them tomorrow afternoon when I get home from work, just to make sure.
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Andy - '66 122s, '79 264