ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Technical Talk > Suspension and Braking Chat
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      02-07-2015, 07:19 AM   #1
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

Shimmy while braking: deposits?

Working through my first month with the 07m coupe. 45k on the odometer. 700 miles of that is my doing. Daily driver for me. All stock brakes and pads (God the dust...)

The cpo I had done before purchase indicated that the brakes were still fine in relation to depth, etc. pads were at 10mm rear and 12mm front.

I noticed last week that there's a slight shimmy under light braking when coming to a stop. It wasn't there (or I didn't notice it) prior to last week. I'm fairly certain I would have felt it.

Was in the dealership yesterday for a full balance and alignment and of course the dealership immediately says warped rotors but it doesn't look like they did any analysis, just knee jerk reaction and greed.

From reading through the forums it seems like it might be pad deposits and not rotor issues? I'm leaning that direction as well simply because:

I haven't driven it hard at all.
I've been washing it frequently (stupid stupid brake dust)
It's been cold here in NC lately.

Am I missing anything? Would some spirited driving and braking help to wear off deposits or is more intervention required (garnet paper and scrubbing)

I'm already going to replace the pads because of the obscene levels of dust so if the rotors need to go as well I would rather do it in one shot. Just trying to see what additional troubleshooting I can do myself. Obviously a rotor runout would be the next step to confirm warping. Was just hoping there were some things I could do that wouldn't require pulling things off etc.
Appreciate 0
      02-07-2015, 10:58 AM   #2
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

More testing: no shimmy on hard braking (50mph to 10) and it seems like it only gives a light shimmy on the first application of brakes.

For example: If I use the brakes to slow my speed, like when approaching a stop light. The first application of brakes gives a slight shimmy to the steering wheel. The next application, to come to a complete stop, doesn't result in the shimmy.

Is this just because of the brakes warming up on first application and my unfamiliarity with the car? It's not severe by any means, and my brain is probably exaggerating it somewhat as well, but it is there.
Appreciate 0
      02-07-2015, 12:13 PM   #3
Caddyshk
M = Midlife Crisis
Caddyshk's Avatar
Canada
65
Rep
2,006
Posts

Drives: 2006 Z4MC Interlagos
Join Date: May 2007
Location: Fort Erie, Ontario, Canada

iTrader: (0)

The OE Pads will leave rust on the rotors after washing. If memory serves me, a few applications of the brakes bring things back to normal. I also recall feeling the sensation of the drilled rotors when braking from speed when I first got the car. I believe it's next to, or impossible to warp floating rotors. Buy a digital caliper device and measure the rotors to check if they're still in spec. Based on your mileage they may be close to done. I would personally recommend StopTech Street Performance pads as a replacement for the OE Pads. Very little dust and perform very well in most situations. Tire Rack has good pricing on the pads. Turner Motor Sports has deals on the OE Rotors from time to time.
__________________
2006 Z4MC - #LL93158
SS Race Cans, RE X Pipe, DKF Sec 1, Fabspeed Headers, OE STB, AS Shifter, Dave Z CDV, GC Coil Overs, Stoptech lines, Hawk DTC Pads, RE Clutch Stop, RE Transmission Mounts, Vibra-Technics Engine Mounts, Poly FCAB & RTAB, LeatherZ M Shift Boot, Tekarbon Rear Spoiler, CF Grills, Advan RS DGM
Appreciate 0
      02-07-2015, 02:26 PM   #4
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

Thanks for the sanity check. I'm think I'm leaning towards the r1 concept premier series drilled and slotted with ceramic pads. Have seen good comments on here and haven't seen anyone say anything bad about them.
Appreciate 0
      02-17-2015, 06:03 PM   #5
babyfaby
Private
France
14
Rep
96
Posts

Drives: 530D G30/Z4 E86 3.0SI/320i E30
Join Date: Jan 2006
Location: Paris

iTrader: (0)

Hi,

This Shimmy is due to your control arm bushings. At the first brake application they take their place (causing shimmy and a steering wheel movement) and at the second one, the shimmy is not here anymore till you continue driving few miles and start braking again.

I experienced it and changed the bushings
Appreciate 0
      02-17-2015, 06:58 PM   #6
The HACK
Midlife Crises Racing Silent but Deadly Class
The HACK's Avatar
1817
Rep
5,337
Posts

Drives: 2006 MZ4C, 2021 Tesla Model 3
Join Date: Oct 2007
Location: Welcome to Jamaica have a nice day

iTrader: (1)

Quote:
Originally Posted by babyfaby View Post
Hi,

This Shimmy is due to your control arm bushings. At the first brake application they take their place (causing shimmy and a steering wheel movement) and at the second one, the shimmy is not here anymore till you continue driving few miles and start braking again.

I experienced it and changed the bushings
This.

From what you describe it is unlikely it's from brake deposit, but given the age of our cars, it is HIGHLY likely that it's from the front control arm bushings deflecting.
__________________
Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
Appreciate 0
      02-18-2015, 02:27 PM   #7
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

Thanks! Another part to replace

What's the best replacement? I see some notes about Rogue Engineering making an upgraded version but I don't see anything that calls out the Z4M version?
Appreciate 0
      02-18-2015, 05:03 PM   #8
babyfaby
Private
France
14
Rep
96
Posts

Drives: 530D G30/Z4 E86 3.0SI/320i E30
Join Date: Jan 2006
Location: Paris

iTrader: (0)

I don't know if you can get them, but the Meyle HD do a great job.
Appreciate 0
      02-18-2015, 05:04 PM   #9
babyfaby
Private
France
14
Rep
96
Posts

Drives: 530D G30/Z4 E86 3.0SI/320i E30
Join Date: Jan 2006
Location: Paris

iTrader: (0)

I don't know if you can get them, but the Meyle HD do a great job.
I suggest to change them before changing any part on the brake system. It's cheap and 99% you won't need to buy other parts.
Appreciate 0
      02-18-2015, 05:26 PM   #10
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

These?

I can't figure out if they are or aren't compatible with the z4m as it says both.

http://store.bimmerworld.com/meyle-h...sets-p704.aspx
Appreciate 0
      02-18-2015, 06:44 PM   #11
The HACK
Midlife Crises Racing Silent but Deadly Class
The HACK's Avatar
1817
Rep
5,337
Posts

Drives: 2006 MZ4C, 2021 Tesla Model 3
Join Date: Oct 2007
Location: Welcome to Jamaica have a nice day

iTrader: (1)

Those will likely "fit" but won't give you the increased caster angle that the offset bushings that came on the MZ4s will.
__________________
Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
Appreciate 0
      02-18-2015, 07:14 PM   #12
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

I think I'll stick with OEM to prevent guesswork on this one.
Appreciate 0
      02-19-2015, 06:55 AM   #13
babyfaby
Private
France
14
Rep
96
Posts

Drives: 530D G30/Z4 E86 3.0SI/320i E30
Join Date: Jan 2006
Location: Paris

iTrader: (0)

Yes, better to stick with OEM if there's a different caster angle on your Z4M. My Z4 is a 3.0SI.
Maybe for you the opportunity to change for a Powerflex solution.

Last edited by babyfaby; 02-19-2015 at 07:09 AM..
Appreciate 0
      02-19-2015, 07:43 AM   #14
tikamak
Captain
Lebanon
58
Rep
912
Posts

Drives: 2006 Z4M Roadster TiAG/black
Join Date: Jun 2011
Location: Beirut

iTrader: (0)

What does shimmy mean ?
Appreciate 0
      02-19-2015, 08:51 AM   #15
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

a light repetitive shaking back and forth. In this case the steering wheel.
Appreciate 0
      02-19-2015, 09:39 AM   #16
babyfaby
Private
France
14
Rep
96
Posts

Drives: 530D G30/Z4 E86 3.0SI/320i E30
Join Date: Jan 2006
Location: Paris

iTrader: (0)

Consider it as vibrations
Appreciate 0
      03-27-2015, 08:15 AM   #17
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

Quote:
Originally Posted by babyfaby View Post
Hi,

This Shimmy is due to your control arm bushings. At the first brake application they take their place (causing shimmy and a steering wheel movement) and at the second one, the shimmy is not here anymore till you continue driving few miles and start braking again.

I experienced it and changed the bushings
Finally back from vacation and got the car in this morning to have the FCABs swapped.

FIXED!

Thank you so much for the diagnoses.
Appreciate 0
      05-01-2015, 06:36 PM   #18
babyfaby
Private
France
14
Rep
96
Posts

Drives: 530D G30/Z4 E86 3.0SI/320i E30
Join Date: Jan 2006
Location: Paris

iTrader: (0)

Happy to read it
Appreciate 0
      08-10-2015, 10:36 PM   #19
mcoupe5/6
Private First Class
mcoupe5/6's Avatar
8
Rep
165
Posts

Drives: 08 M Coupe
Join Date: Aug 2012
Location: houston

iTrader: (0)

Excellent to hear your problem is resolved. I am having this issue also, time to swap the bushings.
Is oem best or will poly bushings give better results and wear?
Appreciate 0
      08-28-2015, 07:24 PM   #20
JCF
Second Lieutenant
32
Rep
217
Posts

Drives: 07 Z4 M Coupe
Join Date: Jan 2015
Location: Charlotte, NC

iTrader: (0)

Not sure. I went with OEM simply because the Indy I use doesn't do aftermarket. Poly might transfer more vibration...
Appreciate 0
      09-08-2015, 08:22 AM   #21
Daemonblitz
Commander
Daemonblitz's Avatar
219
Rep
850
Posts

Drives: Z4MC/M5/640iX/M1000RR
Join Date: Nov 2010
Location: Aurora, ON, Canada

iTrader: (6)

Garage List
2008 BMW M5  [9.50]
2006 Z4M Coupe  [8.77]
2010 BMW S1000RR  [10.00]
Glad we have such a great source of information for our cars on this amazing forum, keep it up everyone !
I have been through the same issue, and have actually gone down the road of "fixing a brake issue" only to have the shimmy still there, mine happens to be very intermittent, sometimes it will be smooth braking and other times it shakes quite badly. Will get FCABs done and will report back here after I get to test it out on the next track day.
__________________
E86 ///M Coupe - Imola Red/Imola Red
E60 ///M5 - (6 Speed) Silverstone Metallic/Black
F06 640iX - Tanzanite Blue/Amaro Brown
K66 ///M1000RR - Competition
Appreciate 0
      09-08-2015, 04:46 PM   #22
Kim Schwartz
Private First Class
10
Rep
129
Posts

Drives: 128i
Join Date: Aug 2010
Location: Albuquerque

iTrader: (0)

I get a similar vibration vary intermittently. Most of the time it is fine. Once it was very bad in grid lock stop and go traffic and other times on a track with the brakes hot. I have replaced the FCAB abd RTAB with urethane from Pawerflex and had the alignment done. I haven't been to the track recently but it still happens occasionally on the street. Hmmmm? I have Bavauto slotted drilled rotors with cool carbon pads. Any thoughts?
Appreciate 0
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -5. The time now is 07:33 AM.




zpost
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST