stumped on 50-60mph shimmy

[MO525]

When you replace the arms, don't get the cheap ones! There are a couple of brands available...one is solid, the other you'll end up replacing much sooner. (someone chime in with names here...lemforder is good/bad?)

That is THE brand to use when you replace the Thrust Arms.

[MO525]

jplacson...this thread is a perfect showcase as to why piece mealing a front suspension is problematic. Shimmy as mentioned is a function of really everything. Yes the thrust arms are the biggest contributor but everything has to be in relatively good condition to mitigate vibration. Sounds as though you replaced your thrust arm bushings but not the thrust arms themselves. Now you have to go back in and replace the thrust arms if you want to quiet the vibration. Then there is the lower arms and the tie rods etc etc. Everybody wants a silver bullet to conserve cost. At the end of the day you end up spending more by increasing the labor cost of going in each time and chipping away...reality is everything has to be in pretty good shape for the suspension to work properly. There isn't any magic to getting rid of shimmy.
Good Luck,
George

I understand completely, George.
I'm just as "guilty" as the fella who started this thread.
Problem being, I cannot cough up $700+ in parts to replace everything and my unpredictable work schedule doesn't allow a two-day stretch to be planned for such things....heck, that's barring ANY complications, too.
Thank goodness I do all my own repairs or that $700 would be tripled, I'm sure-even at an indy shop.

I do my repairs as funds and time are available.

My shimmy is just barely noticable and merely an annoyance but I want to correct it and I will.....as time and funds allow.
The inner-most driver side tie rod end has a WEE bit of play in it and that appears to be the only questionable one of the SIX on that steering linkage!

This constant "tinkering" with my E34 has given me a REAL good understanding of the undercarriage and inner-workings of it.
Truth be told? I do enjoy it!
German engineering is truly impressive.....a bit "odd" sometimes but impressive, nonetheless.

Other than that little shimmy, I've covered most of the "It's GOING to happen to your E34" items.
We LOVE the car, folks.
If you're in the market for an E34, DO IT.
With places like BMA around and the Bentley manual, how can you go wrong?
Unless the car is total crap to begin with (HAVE IT CHECKED BEFORE YOU BUY IT!!!), you CAN have a SWEET Bimmer for less than the cost of some new Korean econo-box or a used Chebby.

[jplacson]

Well, I usually get BMW OEM... aren't those the lemforder? it's kinda tough here since they usually only sell OEM.

But if I do have to have my lower control arms replaced, I was thinking of changing them with the aluminum E34 M5 arms... are these compatible with any E34?

[jplacson]

All right! Thanks Paul... I will specify that next time. Will have to bring it in for the rear suspension anyway since I noticed a 'clunk' during cornering.

[George M]

well said Mo525...most of us are on a budget for repairing these cars (I am) and why this board is so indispensible to managing costs through sharing DIY info. And yes the bond we have with these cars that others don't is many of us are gearheads and by doing all the repairs, one really does develop an appreciation for the engineering albeit sometimes quirky as you say. And jplacson, I suggest you save your money are install steel lower arms on your car versus aluminum. You won't feel the difference in unsprung mass on the street.
George

[bofh]

I suggest you save your money are install steel lower arms on your car versus aluminum. You won't feel the difference in unsprung mass on the street.
George

Does this mean that you can use the Aluminum arms in a car that didn't come with them?

Is the only difference with the aluminum arms, less weight?

I just replaced my on Friday, and was thinking about go to aluminum, but thought better of it, and got OEM replacements. Now, I'm just curious.

[George M]

Yup can use aluminum in cars whether they came with them on not. Most don't...I don't for example. Pretty much the only difference is weight...and not proportionate to the density diff between aluminum and steel as aluminum has a lower yield strength so has to be actually larger than the steel arm (more volume/section modulus) to compensate which erodes some of the weight savings.
Think you made the right choice with steel :-)...believe even the most discerning could never tell the difference on the street or track.
HTH,
George

[jplacson]

Oh ok... so better to stick with the standard steel arms. Thanks again!

[TimGinCentralNJ]

Hi Shauhin-

I've had some experience with a shimmy on various E28's, and my last E34, but the only time I ever experienced what you've described occurred on my last E28 as the result of my left front brake caliper beginning to seize on me. It began after the first panic-stop I'd ever done in the car, and although you couldn't even tell the caliper was grabbing (meaning, there was no pull to the right, the car handled perfectly), it was just enough to create bone-jarring cavitations around 40-50. Sometimes I could jerk the wheel enough to free it, but not always.

Not saying you should disregard what the other have said her, only want to add this as a possibility.

Hope this helps,
Tim G.
'91 535iM

at the range of 40-50mph I frequently get a very nasty vibration through my steering wheel and then it spreads to the whole car shaking. it only occurs when i am driving straight get in that speed range. I can only use the word VIOLENT to describe how bad it shakes up my car. I have to jerk the steering wheel back and forth to get rid of it. when moving

I already had the shocks changed, wheels balanced and aligned, thrust arm bushings replaced with 740il bushings, and tie rods tightened.

Anyone have any suggestions or advise please? it does not pose me as dangerous to drive it; its just that if im on a city street and get a 45mph shake, i have to bounce aroudn on the wheel just to get rid of it. on freeway high speeds the car feels solid as ever.


Thanks in advance,

Shauhin

[jplacson]

so a shimmy could also be caused by the brakes? (if the suspension turns out to be ok)