[Jaredtown]

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

 

[KevinC]

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.

 

[thekurgan]

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.

 

[doc$holliday]

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

 

[fmcfad01]

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.

 

[StephenVA]

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.

 

[fmcfad01]

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.

 

[engin555]

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

 

[fmcfad01]

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.

 

[engin555]

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.....

 

[natxo_e39]

Steering box clearance?

 

[KevinC]

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?

 

[usce]

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!

 

[KevinC]

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

 

[xrviz]

Did you replace the thrust arm bushings yourself? If not, are you sure the thrust arms were tightened with the suspension loaded? If this was done wrong it might explain why you get the shakes when cold but not after the bush softens up.

 

[m5 deamon]

kevin before the shop does another alignment i would put the car on the rack loosen the lower and upper control arms jounce the car up and down and re torque to spec If i remember correctly lower control arm bushing side is 70nm and upper is 125nm. take it for a ride then check the alignment

 

[Sailor24]

I liked the steering box answer, but I also like the idea of re-torquing the control arms at rest. Steering box was my issue. That little play was allowing bonce between opposite bushings. I tightened the screw up to see and sure enough it was better, but that is not a good thing to do. So I bought a low mileage box, but have not installed it 3 years later. Possibly tightening that screw is not as dangerous as I thought, I have had no issues since it seated to its new depth.
The point being with the car off the wheel will move a bit left to right. How much does yours move?

The other thing not mention that does this is the idler arm bushing, near impossible to tell if it is warn. on replacement though it is noticeable, if at fault.

 

[natxo_e39]

I liked the steering box answer, but I also like the idea of re-torquing the control arms at rest. Steering box was my issue. That little play was allowing bonce between opposite bushings. I tightened the screw up to see and sure enough it was better, but that is not a good thing to do. So I bought a low mileage box, but have not installed it 3 years later. Possibly tightening that screw is not as dangerous as I thought, I have had no issues since it seated to its new depth.
The point being with the car off the wheel will move a bit left to right. How much does yours move?

The other thing not mention that does this is the idler arm bushing, near impossible to tell if it is warn. on replacement though it is noticeable, if at fault.

Interested in the steering box nut adjustment.

Did that fix the clearance?

Pros and cons of doing it?


Nacho

Enviado desde mi Aquaris E5 mediante Tapatalk

 

[KevinC]

Partial update: alignment done yesterday. The rear toe was way out of whack, and now the car tracks MUCH better than it used to. It wandered a lot and required constant correction to keep it on a straight & narrow path. Now it goes where it's pointed with zero wandering. Huge improvement. So I've got that going for me, which is nice.

Too soon to tell if any change in the original problem as the car was warm when I was able to drive it yesterday. Will take it out at some point today and see what's what. Stay tuned.

 

[REKIII]

Did you check if the windshield is loose? The buffeting at higher speeds can cause a vibration, then when the window sealant warms up it goes away.

I'm just kidding. Re-torquing the thrust arm bushings when settled seems like the next best thing to try given your process so far.