Lower control arm bushings are ok? That's the speed where shimmy comes into play if they're shot...

Spacers, yea or nea?

 

No spacers.. you're probably right about the LCABs, sounds logical. Once addressed will report what the fix turned out to be. Thanks.

 

Do you ever hear your brakes squeal? Turning or cruising not braking. Old calipers can bind a bit and this can cause some shakes after it shakes it goes away. One sign is that once it does it, it will not come back until you hit the brakes again.

 

Nope, brakes are behaving fine, and pads were at 90% when I bought it. My money's on the LCABs. Thanks for the suggestions.

 

Mine started to do this as well. I already replaced the lower control arms plus bushings, no spacers on the vehicle, replaced passenger wheel bearing (if that matters). I'll have to see if one of the wheels has a slight bend? Sometimes I do hear my brakes squeak when I go over speed bumps?

 

Well, still no resolution. My indy mechanic (quite experienced with these cars, former dealership master tech) says everything "looks real tight" suspension component-wise. He recommended that he sub it out for a road force rebalance. He has a high-end wheel shop across the street that he trusts implicitly to do the job right. So I went that route. No improvement.

I went back to the last mechanic to work on it before I bought it (4k miles ago) who had replaced the thrust arm bushings at that time, and given it a clean bill of health otherwise. He wants to see the road force figures - but the report that can be produced either wasn't or wasn't saved. It's possible a tire(s) could be causing the problem, but they still have decent tread left, and I hate to throw a pair of Pilot Super Sports at it in the hope it helps, when it may well not.

Any other ideas out there? I gotta get this handled - it's driving me crazy!

 

It's doesn't hurts to looks underneath and inspect the flex disc(Guibo) and CSB.

 

Guibo is brand new, 4k miles ago. CSB? Center support bearing?

 

Csb is center support bearing but that would not cause a font end shake.

If its not the control arms then I would look at the possibility of a bent wheel or tire issue.

 

^^^^ Money on a bent wheel.

 

Would think the runout on the road force would show that though, no?

I still think it sounds like LCA bushings... the speed range is classic for that problem.

 

Dont ignore the rear axle when troubleshooting (brakes, subframe bushes, control arms, wheels/tires etc). Something from the rear could be transmitted to the front.

 

Balancing will show bent wheel. I had a problem like this on one of my cars and it ended up being a combination of two issues, upper control arm bushing and the one brake caliper would hang up and cause a shimmy then release. Also I assume you have wheels with correct center bore, I had to add hub centric rings to a set of wheels because the bore was off slightly and caused shimmy. These things can be a ***** and usually result in a few new front end parts. Good luck.

 

I finally got a good look at the tires - they look like hell! They look old - they are cracking like dry rot between the treads and generally look crappy. Shoulders on fronts a bit more worn that across the rest of the tire. Car was 4-wheel aligned 4k miles ago as I bought it, should be OK now, but I'm going to go ahead and throw a pair of front tires at it next week since it pretty much needs them anyways. If no resolution, I'll go from there. Stay tuned.

 

Most tires in AZ will crack rather quickly for obvious reasons. It does not necessarily indicate a shot tire, depending upon where the cracking is (above tread sipes, no. Halfway down the sidewall, yes). What are the date codes on the tires, what is the tread depth and what psi are you running all-around? Is it worse in the morning while the car is cold? Is there any associated noise with this? Does it get better after the car warms up?

It may seem odd but it could also be motor mounts or any of the rubber mounting components down the line. Also can't rule out a failing bearing on the drive belt system.

I am very sensitive to these things (and super picky) if you would like me to take a look at it for you and see if I can help pinpoint it. I don't mind.

 

How long has it been since you looked at your Tie Rods, Centerlink, Idler Arm, etc?

 

Thanks for all the replies. Yes, the car is an EAG car, and underwent a thorough mechanical inspection + a ton of work done before I bought it, just 4k miles ago. Included was new thrust arm bushings. That was the only suspension area that needed any attention. My own local indy mechanic agrees that everything else up front is solid at this point. Shouldn't be a bent rim as that would have been noticed during the (now 3x) balancing process, especially the last guys who do wheel refurb and would have wanted the straightening job.

I'm going to take Adam up on his offer and have him have a drive and look-see and see if he comes up with any new theories. I'll update this thread as any news becomes available.

 

FWIW, my EAG car also came with new OE thrust arms but they were still too soft. I opted for the HD lower control arms and PF thrust arm bushings and the shimmy went away. I'm not saying your situation is similar, but the OE control arm bushings (4), aren't suitable for the E39 chassis at all.

 

Some really great info in this thread! Kevin, I had pretty much identical problem as you describe and spoke about it recently in my for-sale thread. I got new front tires and the problem went away...so I thought! It seemed gone. Yet only a couple months later, I have seen some resurgence of the 50mph shimmy on certain road surfaces.

When I did the tires, all four were road-balanced so I *think* that should exclude problems of a bent rim, correct?

I would have to go through my records again but I know I did Lemforder thrust arms with HD bushings very recently as well as new tie rod ends. Thought lower control arms didnt have many miles on them either but can't remember exactly. Lots in this thread seem to suggest those, tho.

Then there's the possibility of brakes coming into play. I've gotten conflicting answers as to whether my front passenger brake caliper is slightly sticking and causing a little drag. Not sure what to make of that but perhaps it is all related to brakes.

Anyhow, I'm interested in your continued investigation, hope you figure it out.

cheers,
SP

 

I replaced almost everything on the front end suspension trying to diagnose a shimmy/shake at 55 (car had 120k miles on it, so needed it all anyway). I don't think any one thing by itself did the trick, but the big culprits are the thrust arm bushings and I think the center tie rod.

I think the thing that finally killed this issue for me was installing dinan monoballs in the thrust arms. Literally get rid of any possible chance of shimmy at the expense of some noise and vibration.

 

The solution is always, when in doubt replace everything with a known good part. Congrats on resolving that one. Scott your spreadsheet needs updating. I leverage your efforts on my own projects.

 

Hey Steve! That spreadsheet hasn't been updated in a while because I haven't had any issues or problems worth fixing in quite some time.

That said, your wish is my command. On the way to work today I noticed a rough idle and my check engine light came on. Car seems to really hate the cold. Having some strage electrical issues too...like the blower for the heat doesn't come on until the car warms up slightly...like zero flow. In the last day or two, the fastest setting on windshield wipers stopped being faster than the normal speed.

I also had an issue last summer where when I got out of the car, got back in, the key wouldn't turn. That happened this morning again for the second time. Not fun.

So maybe the spreadsheet will get some new entries soon. Hello Bimmerzone order.

 

I had very tiny shake at 72mph in the steering wheel.... All ball joints, control arms ( complete) are brand new. I put 50psi air on my front tires and problem solved.... So I am betting my very low mileage Contis are out of shape i already bough 2 new rims from the dealer just in case one was bent... Guess I will keep them for a while . Give it a shot....put high psi and test.. Good luck

 

My dad resorted to high PSI to get rid of the shimmy. That's just a sign that something else is busted...I inherited the problem and fixed it, so now I can run reasonable pressure in my tires.

 

Oops, i do NOT suggest keeping 50psi for long term! Sorry for misunderstanding... That was just to test! Go back to factory spec with new tires.... I assume the tires got out of shape because I was out of country for 4 months! My suggestion of high psi is for testing purposes ONLY.....

 

Roger. I will add that my dad tried the high pressure thing with Sumitumo HTR-Z III tires. Those are/were the worst tires I've ever had on the car. I know a lot of people like them or consider them a good value for the money, but I'd never get those again.

 

Steering box clearance?

 

Update: replaced the front tires with new PSS’s today. Drove home about 8 miles, including through the “wobble” speed many times - was smooth as glass (or as best I could tell on the roads I was on - at least couldn’t notice any problem). Assumed the problem was solved. Decided to go for another ride tonight to confirm. Car sat about 2 hours between drives. Now the problem is back, as bad as ever. As an experiment, I continued to drive for a total of about 40 minutes, to see if the car being warm would have any effect. Hadn’t noted that making a difference before, but figured it was worth trying. Sure enough, by the time I was on the way back home, after about 30 minutes of driving, it had smoothed out again. Not 100% perfect, but very close to it.

So, apparently the car (presumably some suspension component?) being “warm” helps, being cold exacerbates the problem. Does that point anyone to anything in particular?

 

i had almost the EXACT experience as you and it drove me mad, balanced, aligned, checked and checked until i found the right shop. did another alignment and threw away the front tires. smooth like butter now

keep at it and good luck!

 

Interesting. Alignment was next on my list, so on with it.. thanks.