Another shake & shimmy question...

[ScottyWM]

So, I've had a pretty bad 55-65mph shake going on with my car the last few months. Now that I'm driving 50 miles a day at highway speeds I wanted to get it fixed. It's been 75k miles since I last did the control arms, tie rods and front shocks, so I thought it would be the problem. Took it to my trusted mechanic, and he says there is nothing wrong with any of the front end components! Suggests that I get the tires balanced 'on the car'. (I just recently had them balanced with a Hunter Road Force balancer - it made no improvement.) The tires are about 1.5 years old and still look good, but maybe there is a bad one? Flex disc is also okay.

I can feel the shake in the steering wheel and the seats, pretty much the whole car shakes. It doesn't shake all the time though- sometimes it seems to take a while to start up - maybe the tires need to warm up?

Anyone had something like this? Any advice?

[Asamaan]

Does it do it when you are braking, or when you are accelerating? More details might help. You mentioned the whole car shakes, is it more in the steering or you feel it in the seats?

Al
91 535iA

[ScottyWM]

No, braking or accelerating doesn't affect it. For example, yesterday leaving work - after about 5 minutes of stoplights I hit a section where we drive 50-65mph for a long stretch. The first few miles of this there was no shaking. I thought "cool, no shaking". And then it started the shaking, kind of lightly at first and then harder. It shakes the steering and the seats and pretty much the whole car. I'm wondering if it's a bad tire, it may have to warm up before the bad belt in it (or whatever) starts the shaking. I'm thinking I'll switch the spare tire out with each of the tires (starting in the front) and see if it makes any difference.

[mikell]

Checked the shocks all round?

[ScottyWM]

Well, you know, that's a good point. I've got the infamous self-leveling rear suspension. I've had a leaking right side shock for quite a while. Now the left side is also leaking. And I'm pretty sure the bombs (accumulators) have been shot for a while too. So I am tearing that out and replacing it with a standard setup this weekend as a matter of fact! I know that the leaking fluid tends to accumulate inside the wheel, could it accumulate enough to cause out of balance - I doubt it. And would bad rear shocks cause the sterring wheel to shake? The trusted mechanic said the front shocks are fine.

[repenttokyo]

i replace my tires, removed 90 percent of the shimmy. the remaining 10 percent is because my right front wheel has been bent slightly. Next year (spring) it goes on the back.

[bsell]

i replace my tires, removed 90 percent of the shimmy. the remaining 10 percent is because my right front wheel has been bent slightly. Next year (spring) it goes on the back.

He is onto something here...

Did you rotate tires to see if the vibe followed the tires? Even to the point of cross rotating?

I had a set of tires on another car where both left sides took more force to roll down the road, causing the car to pull left. Once I bought new tires, the problem went away...who would think the two bad tires out of four would be on the same side?

[ScottyWM]

No I haven't had a chance to try changing the tires yet. But it sure is looking like that might be the problem. The tires only have about 15k miles on them. And since the front suspension has 75k miles on it, I would have bet it was the suspension. I think what I'll do is replace each tire one at a time with the spare and see what happens.

[bimmerred535i]

After rotating your tires around to see if that changes the vibration, I would crawl under the car and give your driveshaft a look. Check to make sure that the six bolt that attach the driveshaft to your differential have not broken. And also see if you have any slop in any of the bearings (center support bearing, as well as the differential drive flange bearing) My bearing in my differential finally blew. So this weekend ill let u know whether or not my vibration has gone away.

I had the same symptoms as you are speaking of for about 10k miles. I would not get vibration in accelerating or braking, but only after the car had warmed up and had been going down the road for about 5 miles at 60-65mph. If you lean your leg against the tunnel do you feel the vibration more than in the seat?

[Scott C]

What is the chance your calipers are hanging up and that is why it comes and goes. When you go 55 and have the shimmy, try applying brake (no cars behind please) to see if it changes....

Scott

[632 Regal]

out of round tires, when they are opposite they are in unison and no shake, once in opposition you will feel it. how much does that take, think a tire more then 1/8 out of round is fine in a Cadillac, you aint driving a cadillac, different suspensions completely.

[ScottyWM]

No, just went out and tried your ideas. Applying the brakes makes no difference in the shaking. And I don't even hardly feel it at all in the tunnel. Will experiment with the tires/wheels this weekend.

[vince]

Could it be a bad cv joint in the back, or at the back of the driveshaft? Or possibly a rear wheel bearing? I had a driveshaft in a 2002 that had a bad u-joint in the back, it was binding (move your wrist back and forth, now pause it in the middle; that's what the u-joint was like), and the shaking was noticeable in the seat more than the steering wheel.

Hope maybe this helps point you in the right direction,

vince