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I have had this happen twice, the last time was yesterday. I put in new strut bearings and replaced shocks over to Koni's several months ago. I love the shocks, but ever since the car has had a slight vibration that varies in intensity. Before I went through the struts, the car was dead solid.

The rest of the story: Yesterday I put in a 100 mile drive to my daughter's place and there is a hill a couple of miles long a few miles from her house that is a pretty good pull. Everything going up the hill was as usual, but when I got to the top and started down the gentle incline on the backside the steering wheel started a wild shimmy. When I accelerated, it was slightly better, but when I coasted it was really bad. When I applied the brakes it was worse yet. I slowed down, took an exit ramp and it pretty much went away. I drove on the to daughter's house without any more problems. I still had the slight shimmy feel, but nothing more than usual.

I got up this morning and drove home with only the usual annoying shimmy.

The shimmy is directly related to wheel speed and is more noticeable around 70, but never really disappears. The first time this happened I rotated the tires to see if that would fix the shimmy thinking I might have a tire balance issue, but that didn't make any difference.

The only thing I have experienced that feels like this at all was a CV joint problem but if that was the problem, it should always have the same symptoms not have this wild shaking and then nothing. CV joints could be the issue with the slight shimmy I always have, but the wild shaking stuff would seem to be a stretch. The car only has 93K on it and while I'm not the original owner I think that is probably correct.

Anybody have a similar experience some thought on where to go looking?
 

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I"m sure you check this already, but have your front tires checked, for the usual suspects, before looking into the suspension. Low pressure or a loose radial belt, both will give a car a awful shimmy/vibration.
Frank L.
94 164 LS
'60 Giulietta Spider
'59 Giulietta Sprint
 

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Anybody have a similar experience some thought on where to go looking?
Goes without saying, but do recheck that strut lower bracket bolts and bottom balljoint bolts are tight. I had a loose strut bracket once on an X1/9 and hardly noticed except for an odd lurch at speed.

-Alex
 

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And the wheel alignment can sometimes be affected by disassembly and re-assembly of the front suspension. If you have excessive toe out or incorrect toe in you can get a bad shimmy. What leads me to suspect the toe is incorrect is the symptom is worse on overun when the front wheels push back against the freeplay in the suspension bushings.

Also, if the new shocks are gas pressure the ride height can be pushed up a bit and front toe is directly related to ride height, as is camber. If you haven't had an alignment recently you've nothing to lose by having one done. The 164 seems to like close to zero toe in front but never positive toe in. If you can't get exactly zero then get the smallest negative toe out the alignment shop can manage.

I think the zero toe works best if you have negative camber close to the maximum permitted on the front tires. If the front camber is less i.e smaller negative degrees, then more toe out is likely a better compromise.

My 164 has excessive front camber from the factory and runs best with zero toe at the front.
 

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If it was perfect before you did the work, well I can only deduce that it has something to do with what you did. Tires don't go bad immediately after doing strut work. Unless you did something to throw the frontend out of alignment and immediately wore a strange pattern on the tires, but that would take some miles first and not right away. I think you are going to have to retrace your work. Lug nuts properly torqued? Do you have non hub-centric aftermarket wheels? Have the strut tower lower mounts been swapped L to R? The strut assemblies are side specific when the parts are assembled. Does the front of the car sit extra high? Could indicate that error. :eek:
Charles
 

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I have had this happen twice, the last time was yesterday. I put in new strut bearings and replaced shocks over to Koni's several months ago. I love the shocks, but ever since the car has had a slight vibration that varies in intensity. Before I went through the struts, the car was dead solid.

The rest of the story: Yesterday I put in a 100 mile drive to my daughter's place and there is a hill a couple of miles long a few miles from her house that is a pretty good pull. Everything going up the hill was as usual, but when I got to the top and started down the gentle incline on the backside the steering wheel started a wild shimmy. When I accelerated, it was slightly better, but when I coasted it was really bad. When I applied the brakes it was worse yet. I slowed down, took an exit ramp and it pretty much went away. I drove on the to daughter's house without any more problems. I still had the slight shimmy feel, but nothing more than usual.

I got up this morning and drove home with only the usual annoying shimmy.

The shimmy is directly related to wheel speed and is more noticeable around 70, but never really disappears. The first time this happened I rotated the tires to see if that would fix the shimmy thinking I might have a tire balance issue, but that didn't make any difference.

The only thing I have experienced that feels like this at all was a CV joint problem but if that was the problem, it should always have the same symptoms not have this wild shaking and then nothing. CV joints could be the issue with the slight shimmy I always have, but the wild shaking stuff would seem to be a stretch. The car only has 93K on it and while I'm not the original owner I think that is probably correct.

Anybody have a similar experience some thought on where to go looking?
I assume the hub was left on the car when the struts where replaced? I am also assuming that you replaced all 4 struts? If removed check spindle nut.
First and foremost did you have an alignment after the install?
If not that is most likely your problem, then wheel balance then, wheel bolts. But the wheel bolts you can check real quick yourself.
Although it sounds like a CV joint issue or drive line issue since it is speed sensitive I would make that your last look as they just don't go bad instantly! Plus most of the time a CV joint won't give bad vibration, more of a clicking then get worse over time.

Nine out of ten times, speed-sensitive vibrations are due to an out-of-balance wheel. But what about the tenth time when balancing doesn't cure the shakes? Is it a bent rim, an out-of-round rim or tire, an off-center wheel or hub, or a bent or imbalanced drive shaft? Sometimes the problem is worn shocks or a loose part in the suspension (in this case) or steering linkage.

Most tire/wheel imbalance problems will make themselves evident at speeds above 45 to 50 mph. A back-and-forth shimmy in the steering wheel means one or both front wheels are dynamically imbalanced, or a rim is bent. A simple bubble balancer can't address either of these.

An off-car electronic spin balancer will check both static and dynamic balance of the tire and wheel assembly. Some balancers can also check radial and lateral runout. But off-car balancers only do the tire and wheel assembly. They do not take into account brake rotors that may be out of balance. So when a vibration problem doesn't go away even though the wheels have been rebalanced, it should tell you the balance problem is probably on the vehicle.

First, try re-indexing the rotor one or two lug positions on the hub to see if that reduces the imbalance. If there is no change, the rotor may need to be balanced or replaced.


I would say it is something simple and something that was overlooked during the install.

Jason
 

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Discussion Starter #8
Thanks for all the replies. I did not have the car aligned after the shock replacement, so I am going to try that first. ChazzyD is right on the mark, in that it was good before the shocks, so must be something I did. I replaced each strut separately so no chance of swapping parts between struts. I have checked the bolt torque on wheels and struts.

Just as a double check, near as I could tell from my CarDisk, 50lbs is needed on struts. Can anyone verify that?
Thanks.
 

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Another possibility ... you might want to check steering play too (tie rods in particular) . I would think having some steering play and perhaps some toe-out might result in what you described. You said there is no problem when going up hill - the front wheels in this case are under constant load in one direction (to pull the car up hill) so the wheels stay in one position and do not "wobble" much. But when the car is going down hill or braking, the force of the car applying on the front wheels would fluctuate more. If there's some steering play, the amount of toe-in/out would also changes to the extent allowable by the steering play. This might result in some front wheels wobbling movements.
 

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Maybe steering rack bushes? Mine didn't shimmy (just pulled badly to one side) but I didn't drive it very far or fast with dud rack bushes. I would guess that the car would shimmy pretty badly at speed if you were backing off though. The 164 suspension is pretty simple, if it's still got a bad shimmy after running a spanner over all the fasteners, I'd take it to an alignment shop you trust and see what they come up with.
 
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