Lift the car up, put your hands on the wheel and check for play. Optionally, have a second person do that while you keep your eye on the ball joints for movement.
'98 740il | 9/97 build | schwarz 2 | sandbeige | 5AT | 270k
'04 330i ZHP sedan | Mystic blue | Alcantara | 6MT | 120k
'00 540i sport | Titanium silver | Black | 5AT | 152k
'85 Mustang GT convertible | Medium charcoal metallic | Gray | 5MT | 216k | one owner, all original
mods: m-pars | Bilsteins & B&G springs | ValentineOne | StealthOne
retrofits: full nav | MKIV | bluetooth TCU | BM53 w/ AUX input | video module w/ AV input & backup cam | oem sirius xm | xenon | shades | PDC | rain sensor | BMW DWS TPMS | lighted door handles | front seat heaters | heated steering wheel | euro rear fog lights | ski pass | folding mirrors
I am also going through this shimmy myself although it is in the 60-70mph range. My tires were feathered and cupped, brake rotors were warped and shook violently to braking at speeds. Resurfaced rotor and new pads took care if the braking symptom, new tires took car of most of the steering wheel shimmy but i could still notice the shimmy ever so slight. Even had the upper and lower control arms changed recently as well. I know if i let it go all of the tir and brake issues will come back. Any suggestions?
edit: the rotors were actually replaced with oem rotors not resurfaced and new pads used are carbotech pads. I mixed it up with my other car.
Last edited by shenofjo; 05-29-2017 at 05:29 PM. Reason: Correcting wrong Info
Resurfacing cheap rotors won't work on the E38. You need to replace them with OEM rotors and pads and stay away from aftermarket stuff for brakes. Period.
As for the shimmy at speed, this is almost always caused by a wheel/tire balance problem, NOT thrust arms. Only shimmy below 50mph is likely to be a suspension issue.
Frankie, you make good points. The first thing that should be done is always to balance the wheels and check for runout with the tires. I concur about replacing the rotors and not resurfacing them. I had bad rotors a few months ago, which caused a really bad shake on braking, but after replacing them things were much better, but the shimmy and vibration was still there.
However, bad thrust arms (any arms really) CAN cause a shimmy at speed. I just replaced mine a few months ago to solve my vibration. It wasn't the bushing, but rather the ball joint (maybe damaged by the rotors?). I found it by lifting the car and checking for play. The steering knuckle was slightly moving at the ball joint of the thrust arm. But, definitely, always do the easy things first: check the tires and rotors!
With these suspensions, there are 4 points of stabilization for the front wheels: the strut, uppper control arm (thrust arm), lower control arm, and tie rods/centerlink. The stability offered by the strut is obvious. The lower control arm gives the front steering knuckle stability in the "camber direction," the upper control arm provides stability in the "caster direction," and the tie rods stabilize the wheel in the "toe" direction. Hard to explain, but if you look at the placement of the arms, the upper arms take the brunt of the wheel wanting to travel backwards, as in hitting a bump or heavy braking. The lower arms take a lot of abuse in turns and bumps. The tie rods take abuse in turning and even when travelling straight down the road to hold both front wheel steady. If there is ANY play in those ball joints or bushings, it will directly translate to movement of the wheel on the car = shimmy.
The key to the suspension of these cars is to replace everything together. Because there is overlap in the dimension that each component stabilizes, replacing one component can offer initial stability, but will wear faster and ultimately re-reveal the shimmy that was initially taken care of. I've noticed that it is a combination of parts that usually add up to what we feel as "shimmy" in these cars. So often we replace the upper arms, things are great, then 3-6 months later, the car isn't perfectly smooth. Chances are there is a little play in the lower arms and/or tie rods. I'd say besides tires or rotors, the U/L arms are the culprit 80% of the time. The tie rods or centerlink take up the rest.
Disclaimer: this is all from empirical experience and just opinions I have formed over the years of replacing the suspension on my 740 and 540.
Edit: wtf is wrong with the posting and editing on the forum? it keeps warning me that I am leaving the page and doesn't post? and editing doesn't work when you first click save?
Last edited by racer2086; 05-29-2017 at 12:40 PM.
'98 740il | 9/97 build | schwarz 2 | sandbeige | 5AT | 270k
'04 330i ZHP sedan | Mystic blue | Alcantara | 6MT | 120k
'00 540i sport | Titanium silver | Black | 5AT | 152k
'85 Mustang GT convertible | Medium charcoal metallic | Gray | 5MT | 216k | one owner, all original
mods: m-pars | Bilsteins & B&G springs | ValentineOne | StealthOne
retrofits: full nav | MKIV | bluetooth TCU | BM53 w/ AUX input | video module w/ AV input & backup cam | oem sirius xm | xenon | shades | PDC | rain sensor | BMW DWS TPMS | lighted door handles | front seat heaters | heated steering wheel | euro rear fog lights | ski pass | folding mirrors
Update. So last night I was driving home on a mountain road and I noticed that when cruising right at about 50mph, there would be an extremely tiny shimmy, but the second I hit the brakes it became brutal. I can take the car back to the shop that did my rotors before perhaps or maybe a smaller shop to ask for a balance and rotate if you folks think that would help, but even I am starting to think this is a case of rotors.
Yeah, if shaking on braking then it's most likely brake related. Updated my info on previous post and I don't have issues to braking at all now. I was being conservative with switching out the suspension parts and I think it might be in my best interest to swap out the rest while most of the parts I put in just recently are still intact..hopefully. I'll bring it in to the suspension shop and have him check it one more time before throwing more parts at it. Maybe one of them tape weights came off.
'98 740il | 9/97 build | schwarz 2 | sandbeige | 5AT | 270k
'04 330i ZHP sedan | Mystic blue | Alcantara | 6MT | 120k
'00 540i sport | Titanium silver | Black | 5AT | 152k
'85 Mustang GT convertible | Medium charcoal metallic | Gray | 5MT | 216k | one owner, all original
mods: m-pars | Bilsteins & B&G springs | ValentineOne | StealthOne
retrofits: full nav | MKIV | bluetooth TCU | BM53 w/ AUX input | video module w/ AV input & backup cam | oem sirius xm | xenon | shades | PDC | rain sensor | BMW DWS TPMS | lighted door handles | front seat heaters | heated steering wheel | euro rear fog lights | ski pass | folding mirrors
Back to ground Zero, Xpro... at 125K you probably have more than one issue causing a combined shimmy feel, and not from your brakes (rotor pulsation would be noticed consistently down to slow rolling speeds).
With the car on the ground, forcefully push down each front corner. You should feel significant resistance down, with an immediate 'up' return with no bounce. Easy down with easy return your struts are worn.
Jack each side up individually, jack-stand it at the pad. Place a floor jack under the wheel area and use a block of hard wood to 'preload' the suspension until the car is just barely off the jack stand. Be sure to catch the block on the center part of the knuckle, NOT the control arms. Forcefully wiggle the tire with your hands at 9 and 3 o'clock position and look for any play in the thrust arm, tie-rod end, and control strut. It will take a bit of force wiggling to cause visual movement, unless you have a totally wipe component.
Let it down, do the other side. The suspension must be preloaded to it's normal ride position. Just jacked and hanging to the limits puts tension on components that eliminate play that could be causing your concern.
My guess is you have some loose dampening in the struts along with worn thrust arm bushings, and possibly some tie-rod end play contributing to your mid-speed shimmy, made worse by weight shift under braking. Most replacement can be DIY, with the exception of alignment (and some do that too). Many good tips/links on the forum for suspension work.
Diagnose fully before throwing parts at it. If possible, look up a forum member from the South Bay area that has experience with the same scenario. Maybe they can shed a ray of light.
South Bay crew? I'm sure beers could be had....
Last edited by oldroller; 05-30-2017 at 06:47 PM. Reason: spelling
looking at $20 road force balancing per tire at the America's Tires. will find out tomorrow if it works out!
To oldroller, I do think my car might have multiple issues, I'm going to have the tires rotated and balanced as they are probably due not to mention having them poke around and see, I want to say its not the rotors since I just spent some good money on those and I don't feel the lumps like I did before, but in the end I plan to do everything DIY even if it includes buying some tools as I'm sure throwing money at it from a shop will cost me 3-5x more than DIY and most of these components should be easy to work with.
im afraid to jinx it since i been driving with variate amount of shimmy for so long that it almost feels weird without it. but, i want to update that the road force balance seems to have done the trick! one of the tire required 180 degree tire mounting and the rest were left untouched. more long term testing needed.
Grats! Hope it lasts! Mine has been shimmy free since I purchased the new tires and road force balance. I absolutely hate vibrations, shimmy, bad tracking, wheel hop, etc. and my steering wheel has to be perfectly centered. I was skeptical at first about the road force balancing but it does work.
Well for anyone with the same issues, start from the basics. I did a tire rotate and balance from Big O Tires (non road force) for free since I bought tires through them. They said the tires were super unbalanced, and since having the car back the issue has cut in half or quarter, I consider it much more driveable now, but I still have a shimmy and this time its a bit more noticeable when not braking, which leads me to believe it's back to not the rotors, you guys are saying jack up the car and check for play, or should I do the look at the tires when breaking from head on?
Edit: after a few days of driving, the issue has pretty much gotten back as bad as it was before.
Last edited by Xproplayer; 06-11-2017 at 07:45 PM. Reason: new information
Xpro, for a start I would move the tires around, front to back if you have the same size rims. The shimmy should 'change' if it is tire related.
If no change then look at front suspension gear. My '01 had a slight shimmy, came and went, depended on road surface/time driving/etc. No probs braking.
Eventually I replaced the thrust arms even though I could not get much movement out of the originals when doing the 9/3 o'clock wiggle test.
The big bushings are exceptionally soft, which supplies the most supple ride, but these cars are heavy and conditions can cause a shimmy when normal tests will reveal no play.
The new arms cured the intermittent shimmy felt in the wheel, steady at all speeds.
There are arms with polyurethane bushings out there, but the harder composition kills the fantastic road feel of the E38.
Btw, looking at your tires when braking will reveal no answers....other than a good look at your car head on...might be a good pic!
Well I'm going to start attacking this head on and replacing parts, would I possibly gain any benefit from swapping the front and rear rotors? My rear rotors should still be OEM and the front ones are the ones that were replaced. Since the balance and rotate I have found a larger shimmy around 50mph but it's still far far worse when braking, if someone can confidently tell me a part to replace, even those front rotors, I'll do it.
And I gave my suggestion, since it's happening even when not braking, it's not the rotors.
There are two things that will make the car shake worse when braking: bad rotors and/or bad thrust arms (upper control arms -- s-shaped arm).
You need to diagnose between those two. You could throw parts at it, but it could also be a combination of both.
How do you diagnose it?
For the rotors, I would say the easiest if you get lucky is that if you brake moderately from 35 mph down to 0 mph (as though coming to a stop for a light) and you feel anything in the brake pedal or you feel the car "pulsing" to a stop, you have a rotor issue. You may not feel it in the pedal but if you feel the car grabbing and smoothing grabbing and smoothing (for lack of a better term), then your rotors are not true.
A more scientific approach would be to remove the wheel, set up a runout gauge, and spin the rotor to check for lateral runout. If there is any, replace the rotors.
For the thrust arms, they are harder to diagnose if it is the bushing that is bad, but not visibly torn. You can test the ball joint by jacking the front of the car off the ground and wiggling the wheel at 3 and 9 o'clock. You should have a friend do this for you while you look at the ball joints from underneath. If there is any movement, you need to isolate at which ball joint it is happening. You have to look at it for that.
Keep in mind, the tie rods could also be a culprit for the 3-9 play.
Personally, I think your thrust arms are bad because I just went through this. A shimmy on the road and under braking that I couldn't get rid of. Arms seemed perfectly fine, but after replacing them, my car is rock solid.
Do not discount the rotors, since, you know, I'm sitting behind a computer and not looking at your car
Last edited by racer2086; 06-12-2017 at 02:20 PM.
'98 740il | 9/97 build | schwarz 2 | sandbeige | 5AT | 270k
'04 330i ZHP sedan | Mystic blue | Alcantara | 6MT | 120k
'00 540i sport | Titanium silver | Black | 5AT | 152k
'85 Mustang GT convertible | Medium charcoal metallic | Gray | 5MT | 216k | one owner, all original
mods: m-pars | Bilsteins & B&G springs | ValentineOne | StealthOne
retrofits: full nav | MKIV | bluetooth TCU | BM53 w/ AUX input | video module w/ AV input & backup cam | oem sirius xm | xenon | shades | PDC | rain sensor | BMW DWS TPMS | lighted door handles | front seat heaters | heated steering wheel | euro rear fog lights | ski pass | folding mirrors
I think it could be multiple issues as well given the cars age, (just hit 137k). In reality I still have a shimmy when not braking, but its worse when braking, when my OEM rotors were bad I felt the pulsing when coming to a stop, I haven't felt that recently, I think I'll start with some suspension components but the testing method everyone keeps mentioning is difficult since I don't know what looks good vs bad.
This is your key. If there is any shimmy at all when not braking, and it gets significantly worse when braking, it is the thrust arms. This perfectly describes my previous situation, I replaced both the upper and lower arms at the same time and the shimmy under braking went away.
After a few weeks I noticed that there is still a slight shimmy present at speed, which is more like 1/8" in deflection. It doesn't get worse under braking. This might be unbalanced rotors, unbalanced wheels (it seems to change in intensity on a given day, which could be due to fluctuating tire pressures or differences in how the two front wheels are oriented to each other), or also most commonly, worn center link/tie rod ends. I will likely need to address it later this year. But the control arms were certainly the cause of my major issue.
If you are in doubt at all or want peace of mind, take it to a shop. I did, partially because it was early on in my ownership and for that reason - I wanted peace of mind that these were installed properly. Afterwards, I did my coilover installation myself, and felt more confident that I could have done the control arms myself - but it also seemed that a couple of the nuts on the body side of the upper arms were a bit difficult to access/leverage. Your mileage may vary.
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