Bad shimmy around 45-50MPH front rotors replaced recently

[Aitch]

if possible, get the 750iL arms as the bushings are heavier duty and will last a lot longer in the 740.

The part numbers for the thrust arms are the same between the 750iL and the 740i/iL. OEM there is no difference. As I mentioned earlier, one suggested brand is Meyle HD, in which the HD includes uprated bushings and helps stand up to the weight in these cars.

[shanecarmaster1]

" OFF Topic mode" :
Shanecarmaster1,
I'm really keen on your E38 Preface lift, and did you create a thread on hit ? any more Pics?

Regards,
Chris from france

Chris,

My e38 is a 2001, so it's a facelift. I can add some pics in the "Show Your Ride" thread for you to see

[Chris V]

The part numbers for the thrust arms are the same between the 750iL and the 740i/iL. OEM there is no difference.

Hmm. The rubber bushes in the 750 arms I've seen had smaller voids on every one of them. Maybe all the 750 ones I saw were the Meyle HD.

[racer2086]

Wow this poor guy is getting all kinds of info.

You have a shimmy without the brakes on and then it gets worse with the brakes. Replace the thrust arms. Period.

Your rotors may have pad deposits on them and not be in the best of shape. If you are concerned, re-bed them or replace them with ATE discs, which are OEM. They are relatively cheap ($69 on FCPEuro).

[/thread]

[purplecty]

Wow this poor guy is getting all kinds of info.

You have a shimmy without the brakes on and then it gets worse with the brakes. Replace the thrust arms. Period.

Your rotors may have pad deposits on them and not be in the best of shape. If you are concerned, re-bed them or replace them with ATE discs, which are OEM. They are relatively cheap ($69 on FCPEuro).

I have a similar issue and I am planning on doing the front control arms since this is the only thing i haven't tackled yet on the suspension...

[sirbevo]

This thread makes me want to replace my thrust arms. I still get a slight shimmy ....sometimes between 60-70. I wonder if the new tires I got kinda masked old thrust arms. I did get road force balancing which helped tremendously.

[shanecarmaster1]

This thread makes me want to replace my thrust arms. I still get a slight shimmy ....sometimes between 60-70. I wonder if the new tires I got kinda masked old thrust arms. I did get road force balancing which helped tremendously.

Mine is the same but the thrust arms are only a few weeks old. Had a death wobble, which was the rotors, still had a wobble, replaced the thrust arms, then road force balanced, but I still have a slight wobble. ALL the suspension is a year old. I'm hoping the tires are messed up and that's it.

[ebida3]

Racer2086 I tried to tell him.

Check engine light (CEL) means 'Cost Estimate Large'

[Xproplayer]

So to all the folks who insist on thrust arms, (I mean this in a nice way, I'm getting torn apart by the two sides of this debate) how can you explain the issue going away with new rotors only to come back after a couple months of heavy driving?

[ebida3]

How about this...check the bushings by prying against the arms for play. If they move replace them. They've bad regardless.Of course if they are rock solid look elsewhere.

Check engine light (CEL) means 'Cost Estimate Large'

[geekyjeffy]

Wow this poor guy is getting all kinds of info.

You have a shimmy without the brakes on and then it gets worse with the brakes. Replace the thrust arms. Period.

Your rotors may have pad deposits on them and not be in the best of shape. If you are concerned, re-bed them or replace them with ATE discs, which are OEM. They are relatively cheap ($69 on FCPEuro).

[/thread]

Would this also apply to a 96 e36? I have not replaced the rotors, tires about 1.5 year old and 6 month alignment. The shimmy actually stops after I have ran a few errands... Would you recommend getting the 8 piece or will the 6 or 4 piece kit do the job?

https://www.fcpeuro.com/BMW-parts/32...79&m=20&page=1

E: sorry for the hijack

[oldroller]

If your shimmy goes away after a bit of driving, you probably have a tire with a weak or shifting radial belt that diminishes after tire warm-up.
I found out the hard/expensive way that these cars are sensitive. I had a shimmy wobble (from heavy to light) that would come and go, very irregular.
Not knowing the history, the components were checked. Torn boots on lower control arms and thrust arms, but no movement when checked, but replaced them.

Center link/tie rods were checked, also had torn boots but no play, replaced them anyway. I always drove after a component replacement. Sometimes it felt good, then BAM.. next day the shimmy was back.
Moved the tires around, and I still had a shimmy, comes and goes, better after running hard a half hour or so. I went nuts on the hunt for the culprit.

I called a friend at a dealership (no, not BMW) and he agreed to pull the wheels and check the balance. Done, all ok within a half ounce or so. No unusual runout. I went home happy, drove fine.
Next morning ripping to work the first 5 miles were aggravating, shimmy shimmy coco bop....then it settled down and drove fine. Stymied, I growled the rest of the day.

I had a spare with a bad tire on the rim so I bought a tire and had it mounted. Before I put it in the boot I decided to switch it with one of the fronts. Next day, same thing. Shimmy, then smooth after 5 miles or so.
Got home and swapped out the other front. Next day, smooth. The day after, smooth. Hmmm.

On a whim I took it by the friend and he had it mounted on the balancer, still in balance, but lo and behimmel looking at the tread as it rotated, there was a visible wobble in the rolling of the tire. Belt shift, or broken allowing
the tire to roll laterally until it warmed up. I replaced the tire, put it back on and have not had a shimmy since. Straight and true.

Sorry for the long saga, but tires issues are not always evident. I should have taken Tim's advice on Meeknet and chased tire issues first before throwing time money and effort into suspension components that were worn, but not causing my issues.
Find a bud with an E38, buy him a bottle to let you try his wheels, swap yours around, road force balance, and do everything to eliminate the possibility that the tires are the issue first.
Just saying...still waiting on my fekkin T-shirt...

[AHolland]

I had this problem and it was severe. Very severe so much so that people sitting beside me could see the steering wheel shaking back and forth about a 1/4" or more. I eliminated warped rotors because you can usually feel warped rotors coming on when you apply light braking and the pulsing that comes from them. Also warped rotors can normally be felt at just about any speed.

I read somewhere that going through the same process to wear in new performance pads as per Stop Techs instructions can help. 5 very hard brakes from 50mph to about 5 MPH but never letting it stop on the rotor. Almost lock them up but not completely. Immediately go up to 40-50 and repeat the 5 times. Then follow that with 5 more runs from 40 t0 5 MPH with moderate to hard braking. Again do not let it ever come to a stop or the hot rotors would burn onto the rotors. I never thought this would work but what the hell. It takes little to give it a try. Now I hardly have any shake when braking from 50 down. It was almost a miracle cure in my car. I did this just recently about 2 weeks ago and I am surprised how much of that shake it too out. I have never seen something like this fix this kind of problem but you really have nothing to lose. Just find a lonely road where people will not think you insane as you go up and down in speed in a frantic fashion.

Good luck.

[Xproplayer]

I had this problem and it was severe. Very severe so much so that people sitting beside me could see the steering wheel shaking back and forth about a 1/4" or more. I eliminated warped rotors because you can usually feel warped rotors coming on when you apply light braking and the pulsing that comes from them. Also warped rotors can normally be felt at just about any speed.

I read somewhere that going through the same process to wear in new performance pads as per Stop Techs instructions can help. 5 very hard brakes from 50mph to about 5 MPH but never letting it stop on the rotor. Almost lock them up but not completely. Immediately go up to 40-50 and repeat the 5 times. Then follow that with 5 more runs from 40 t0 5 MPH with moderate to hard braking. Again do not let it ever come to a stop or the hot rotors would burn onto the rotors. I never thought this would work but what the hell. It takes little to give it a try. Now I hardly have any shake when braking from 50 down. It was almost a miracle cure in my car. I did this just recently about 2 weeks ago and I am surprised how much of that shake it too out. I have never seen something like this fix this kind of problem but you really have nothing to lose. Just find a lonely road where people will not think you insane as you go up and down in speed in a frantic fashion.

Good luck.

Very interesting! I've been thinking its some suspension component as the car just overall just feels loose in the front end when coming to a stop sometimes the tires steer to the left or right when stopping and the fact the shimmy happens when not braking but as a final diagnosis I'm going to take it to a shop and have them lift it up and start checking all the components as a last confirmation.

[ebida3]

Strut rod bushings. Very common exact symptoms. A bump or slight braking can set it off.

Check engine light (CEL) means 'Cost Estimate Large'

[AHolland]

After a long trip I have noticed my shake is back a bit again. I have replaced every single part of the front end so I know it is not the suspension. I think in my case it is the brakes again. I had installed hand controls in my car because I am disabled and I have to bring the brakes and gas up to the steering wheel because I cannot use my legs/feet for those controls. My guess is there is not a big enough neutral spot between the gas and brake actuating and I am heating up the brakes with a tiny bit of drag and that is causing the shake again. I will try to find a time to re-bed the brakes again and I am guessing the shake will be gone again. Last time it disappeared for a couple thousand miles and only this sprited long trip in high heat has brought it back. I can eliminate anything from struts to centerlink as being part of my problem at least. I do know that one of the euro forums had listed some suspension parts as being part of the problem so I am thinking there is more than one way to get this shaking issue.

[mckazok]

You may have weak suspension components but something in the front end has to initiate this vibration.
Did you bed those rotors properly after replacement? I have always had issues with rotors on all my bmws and I tried several proven brands too. Now I have cheapest ebay rotors yet zero issues.

I bed them before starting to drive it daily though. While trying to stop a 2ton vehicle, those front rotors do cause shakes very fast.
So, I hit the highway as soon as I replace the rotors and keep cruising at low gear while applying brakes, they get hot enough to make smoke behind. Let them cool down for a few seconds and reapply brakes.
Driving like this a few miles and you won't have a shimmy when applying brakes for a long time.

And I started using rubber safe lubricant on caliper bushings. Difference is night and day. Even the slightest incline and the car starts rolling on its own. It's CRC 05361 Silaramic Brake System Grease.

[AHolland]

The car came with the brake work already done and I could tell that it was very recent. I know the shop that did it and I suspect the brake and rotors were something economy so I can point to that possibly being a problem. I do not want to swap everything out because the brakes are so new and just bedding them takes away the problem each time. I think I just have to do it again. My suspension should not be a problem because everything has been replaced less than 500 miles ago and that includes new springs, Bilsten struts, strut mounts, you name it, it was done.

It is possible it is a tire and I am changing those too to the new Nokian ZLine AS tires. The person who owned the car before me put a lot of money into replacing the brakes, tires etc so I thought it was okay. However a couple of weeks ago one of the tires blew out completely and came right off the rim. The sidewall was cut right down the middle and the part that sticks to the rim is now long gone. I checked the tire age and found the "NEW" tires are really 12 years old so I am guessing the previous owner got taken on all accounts between brakes, tires etc. I do not want to risk another tire coming off while I am pushing the car so with their age I am just doing a complete swap out for new tires. Between new all season tires and new dedicated winter tires the car will rust away before I wear the tires out. Well I will probably go through two sets of the summer/all season tires. In any case I am thinking that my death rattle might also be coming from the tires so once they are replaced I am going to see if the rattle is gone. If not, I will re-bed the brakes and check it again. I will post what happened here: Tires, Brakes but it would not be the suspension in my case.

[Xproplayer]

Digging up this thread because it might help folks in the future. Long story short, I had / have issues with both. The rotors I got that were non oem have warped. I went to a shop and had the upper thrust arms / upper control arms (the naming on these is weird), additionally they swapped the center link steering link rod, an alignment, and road force balance. This solved all my idle speed shaking and bad shaking when braking, so I have no left and right sway, just pulsing when breaking which they have quoted me $700 + tax on, the other work done was about $1400 + tax