Slight shimmy when braking from 90mph..

[doublevanosrc]

So this morning I noticed a slight shimmy on the steering wheel while braking from 90mph with a nice moderate pedal pressure. I tried to see if it happened at lower speeds and it didn't. The car had new front rotors and pads in Dec 2015 and new tires a few months prior. So I'm guessing it needs an alignment?? Could I be the beginning of something thats gonna get worse?

Thanks.

[Matticus91]

STOP DRIVING IT YOU'RE GOING TO DIE!!!!













Kidding. It's most likely the brake rotors, regardless of if they were replaced a year ago. If you got genuine BMW Brembos they're warrantied for two years under the BMW parts warranty, if they're not genuine BMW, well that could be why they warped but it might also be aggressive driving.

[mackeroni]

I vote for rotors.

[doublevanosrc]

Originally Posted by Matticus91

STOP DRIVING IT YOU'RE GOING TO DIE!!!!













Kidding. It's most likely the brake rotors, regardless of if they were replaced a year ago. If you got genuine BMW Brembos they're warrantied for two years under the BMW parts warranty, if they're not genuine BMW, well that could be why they warped but it might also be aggressive driving.

HA!

Yeah they're 100% OEM however I only drive aggressive about 10% of the time. Most of the time I drive fast (90-95mph) due to the smooth and straight toll roads here.

[NVHoo]

Alignment is not the source of your problem. It is definitely the rotors. Getting them turned will almost certainly solve the problem. Don't let a mechanic tell you they are warped and need replaced. A truly warped rotor is very rare except in track conditions. The cause of an uneven rotor surface is actually deposits of the pad material, dirt, etc on the rotor during its life. Once a deposit area starts at a particular location on a rotor, it continues to get worse as more debris gets attached to the non-metallic spot. As long as your rotors have the minimum required thickness, just get them turned. I'd definitely buy different pads next time

[atr_hugo]

If you can - try this procedure once the current issue is resolved.

http://brakeperformance.com/bedding-in-rotors.php

[NorthernDancer]

Is your wheel nut torque correct?

[doublevanosrc]

Originally Posted by NVHoo

Alignment is not the source of your problem. It is definitely the rotors. Getting them turned will almost certainly solve the problem. Don't let a mechanic tell you they are warped and need replaced. A truly warped rotor is very rare except in track conditions. The cause of an uneven rotor surface is actually deposits of the pad material, dirt, etc on the rotor during its life. Once a deposit area starts at a particular location on a rotor, it continues to get worse as more debris gets attached to the non-metallic spot. As long as your rotors have the minimum required thickness, just get them turned. I'd definitely buy different pads next time

Thanks!

[doublevanosrc]

Originally Posted by NorthernDancer

Is your wheel nut torque correct?

Has always been dealer serviced so I would assume so.

[B777flyboy]

Originally Posted by doublevanosrc

Has always been dealer serviced so I would assume so.

If they didn't tighten on opposite sides and make sure it was fully seated they could have warped it that way.

[iminhell1]

Don't count out bushings.
They claim that the front control arms leak and can cause problems.



There is an update part for this, but I don't know the #.

[doublevanosrc]

Update, after running the same test on different times I noticed that it quit happening. So I went back to the same road where I experienced it for the first time and it did it again. So at this point I can only assume it's on this specific road for some odd reason.

[dandandan]

Im having the exact same issue, although I'm pretty sure the rotor surface is the problem.

Stock pads and rotors.

iminhell1: Is the arm on the left the newer part? Also, is this the non "M3" type?

How do you test control arm bushings for failure while on the car?

[desertman123]

Originally Posted by doublevanosrc

Update, after running the same test on different times I noticed that it quit happening. So I went back to the same road where I experienced it for the first time and it did it again. So at this point I can only assume it's on this specific road for some odd reason.

Tramlining?

[doublevanosrc]

Originally Posted by desertman123

Tramlining?

Yeah that's what I'm thinking.

[doublevanosrc]

Damn shimmy is back now all the time when braking from 80 on any road. I guess its time for a trip to my incompetent dealer.

[mr.fabulous]

control arm bushings

[ejm3]

I had this issue in my Lexus.
Only happened when braking from high speeds, which wasn't very often in an SUV so I just lived with it.

Then a recently got new tires and the problem went away.
I believe one of the front wheels had been out of balance causing the problem.

So don't discount something as simple as a wheel out of balance.

[doublevanosrc]

Went to the stealership to get an alignment since I felt a little pulling to the right, also hoping it would take care of the shimmy. Techs measured the rears brakes and said they would need replacing soon and the fronts were warped which they can do for $1925(all 4). I was no like no worries I would do the brakes myself and told them to proceed with the alignment only. I got the car back and I checked the brake status in i-drive which reads out 35k for the fronts and 60k for the rears. No sure how accurate that is but a visual inspection show plenty of meat on the pads, the rears have less on the pads and are really rusted. I'm planning to do the rears soon.


*On a side note the shimmy is barely noticeable now after the alignment.