Help me diagnose my problem, please!

Cabrio330 · 02-02-2011, 07:04 AM

2004 330i ZHP sedan, steptronic, 60k miles.

Sympton: As I come to a complete stop, the entire car rocks back and forth a couple of times before stopping. Not major, but definitely noticeable.

Cause: Any ideas?

Thanks!

Black_BMW · 02-05-2011, 11:02 AM

Wow I never heard a car could rock back and forth. At what speed did you brake? And does it happen at every complete stop regardless of your speed?

Are you're braking system stock or modified?

Cabrio330 · 02-05-2011, 01:13 PM

Well, it isn't that much back and forth motion, just a little! And it happens almost regardless of speed prior to braking. Brake system is stock.

pyrocrickett · 02-06-2011, 09:09 AM

Fore-to-aft motion could be caused by worn LCAB (front) or RTAB (rear) bushings, as those bits are responsible for locating the suspension on the longitudinal axis (if I remember correctly). Does the motion feel like it's mostly at the front or rear?

pilotlviv · 02-06-2011, 09:55 AM

You should check the brake discs, brake pads, brake calipers with pistons. curvature of the disc, uneven pad wear, failure of one of the piston, caliper mounting wear - all these can cause your problem

Cabrio330 · 02-06-2011, 11:51 AM

It feels like it is mostly in the front. From what little I understand about the physics of automobile suspensions, I would have guessed a bushing failure so thanks for the endorsement! I will start there, but also check the brakes.

Thanks for the helpful replies!

02-02-2011, 07:04 AM	#1
Cabrio330 Registered User Join Date: Oct 2003 Location: Alpharetta Posts: 124 My Ride: 2003 M3 Vert CB/Blk View My Garage	Help me diagnose my problem, please! 2004 330i ZHP sedan, steptronic, 60k miles. Sympton: As I come to a complete stop, the entire car rocks back and forth a couple of times before stopping. Not major, but definitely noticeable. Cause: Any ideas? Thanks!

02-06-2011, 09:09 AM	#4
pyrocrickett Registered User Join Date: Sep 2007 Location: Las Vegas Posts: 100 My Ride: 2004 330i ZHP View My Garage	Fore-to-aft motion could be caused by worn LCAB (front) or RTAB (rear) bushings, as those bits are responsible for locating the suspension on the longitudinal axis (if I remember correctly). Does the motion feel like it's mostly at the front or rear? __________________ '04 ///ZHP sedan 6MT

02-06-2011, 09:55 AM	#5
pilotlviv Registered User Join Date: Feb 2011 Location: Lviv,ua Posts: 60 My Ride: BMW 325xi View My Garage	You should check the brake discs, brake pads, brake calipers with pistons. curvature of the disc, uneven pad wear, failure of one of the piston, caliper mounting wear - all these can cause your problem __________________ Want quickly - fly an airplane, do you want on time - Take the train, you want both - Fly on your BMW our web: www.bmw-club.lviv.ua

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02-05-2011, 11:02 AM	#2
Black_BMW Registered User Join Date: Feb 2011 Location: Jakarta Posts: 201 My Ride: e46 2002 facelift View My Garage	Wow I never heard a car could rock back and forth. At what speed did you brake? And does it happen at every complete stop regardless of your speed? Are you're braking system stock or modified?

02-05-2011, 01:13 PM	#3
Cabrio330 Registered User Join Date: Oct 2003 Location: Alpharetta Posts: 124 My Ride: 2003 M3 Vert CB/Blk View My Garage	Well, it isn't that much back and forth motion, just a little! And it happens almost regardless of speed prior to braking. Brake system is stock.

02-06-2011, 11:51 AM	#6
Cabrio330 Registered User Join Date: Oct 2003 Location: Alpharetta Posts: 124 My Ride: 2003 M3 Vert CB/Blk View My Garage	It feels like it is mostly in the front. From what little I understand about the physics of automobile suspensions, I would have guessed a bushing failure so thanks for the endorsement! I will start there, but also check the brakes. Thanks for the helpful replies!