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
      02-22-2015, 02:55 PM   #1
jaconley
Enlisted Member
3
Rep
35
Posts

Drives: 2007 M Coupe
Join Date: Jan 2011
Location: Sugar Land, TX

iTrader: (1)

Knocking noise in front suspension

Hello. I have a 2007 E86 with two issues that I need your help on that are related to the suspension. The car has 48k miles on it. It also has Vorshlag adjustable camber plates (about 20k old) and a front strut bar. Everything else is stock.

1) When I drive over dips in the road (potholes, or drops between sections of pavement) I hear a sharp knocking noise. The best I can tell is this occurs when the wheel drops from one level to a lower level in the pavement. The noise does not occur on rising travel. I looked under the car, and everything seems solid, and the FCAB bushings do not look cracked. Could something have got loose within the camber plates after driving on them in city streets over a couple years?

2) And maybe it is just me getting older, but the car seems to be riding rougher lately. Even the slightest gaps in the pavement transmit through the car, to my seat and back. It's getting to the point where I just don't like to drive the car anymore unless it is on the smoothest pavement. Could it be that I need to replace all the suspension bushing on the car? I know that when rubber ages, it loses some of its elasticity. I also know that when I replaced the stock camber plates with the Vorshalgs, I expected some NVH, but it seems to be worse now. Should I be replacing the bushings on a 48k mile, eight year old car?

Thanks for any comments and suggestions.
Appreciate 0
      02-22-2015, 04:48 PM   #2
dc_wright
Captain
dc_wright's Avatar
249
Rep
758
Posts

Drives: 2006 Z43.0si Roadster
Join Date: Oct 2014
Location: Orlando, FL

iTrader: (0)

Quote:
Originally Posted by jaconley View Post
Hello. I have a 2007 E86 with two issues that I need your help on that are related to the suspension. The car has 48k miles on it. It also has Vorshlag adjustable camber plates (about 20k old) and a front strut bar. Everything else is stock.

1) When I drive over dips in the road (potholes, or drops between sections of pavement) I hear a sharp knocking noise. The best I can tell is this occurs when the wheel drops from one level to a lower level in the pavement. The noise does not occur on rising travel. I looked under the car, and everything seems solid, and the FCAB bushings do not look cracked. Could something have got loose within the camber plates after driving on them in city streets over a couple years?

2) And maybe it is just me getting older, but the car seems to be riding rougher lately. Even the slightest gaps in the pavement transmit through the car, to my seat and back. It's getting to the point where I just don't like to drive the car anymore unless it is on the smoothest pavement. Could it be that I need to replace all the suspension bushing on the car? I know that when rubber ages, it loses some of its elasticity. I also know that when I replaced the stock camber plates with the Vorshalgs, I expected some NVH, but it seems to be worse now. Should I be replacing the bushings on a 48k mile, eight year old car?

Thanks for any comments and suggestions.
Might be the nut on the top of one of the strut assemblies has loosened a bit. That will definitely give you the knocking noise you describe.
__________________
Top Down 365
Appreciate 0
      02-22-2015, 06:04 PM   #3
zimmer
Second Lieutenant
zimmer's Avatar
United_States
42
Rep
240
Posts

Drives: 2007 Z4MC
Join Date: Jul 2012
Location: NY

iTrader: (0)

Garage List
2007 BMW Z4 M  [2.00]
Check your motor mounts
__________________
Zimmer
Appreciate 0
      02-25-2015, 05:31 PM   #4
DerekSelmanRacing
Second Lieutenant
DerekSelmanRacing's Avatar
United_States
8
Rep
222
Posts

Drives: 05 Z4 3.0 SMG, 01 530
Join Date: Jul 2008
Location: Lake Havasu City, AZ.

iTrader: (0)

I have TC Kline camber plates in mine and had a similar knocking noise begin at about the 2 year mark. Mine have replaceable bearings, but the problem was actually a mushroomed washer which I replaced with a redesigned washer from TCK that was slightly larger diameter and thicker.

Re your ride degradation, could be shocks/struts but it could also simply be aging of the tires...especially if they are run-flats.
Appreciate 0
      03-02-2015, 01:29 PM   #5
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)

At 48K miles your front control arm bushings are likely shot, whether they look it or not. Plus the car is likely over 7 years old now, time to replace it, whether that is the source of your noise or not. Could very well be the source of your ride degradation (besides the fact that the dampers are likely shot as well, or at least, far less effective than when they're new).

Motor-mount related issues should show up while idling at a light as a vibration that can be felt throughout the chassis, but again, if you haven't done so already, the bolts on the mount should be replaced.

I would replace those two parts above first and foremost because they're probably due anyway. If that doesn't solve the issue, it's likely that a bolt attaching the triangulated strut brace to the firewall may have come loose. It's a pretty common problem on earlier Z4 Coupes but is suppose to have been fixed for MY2007. Inspect the bolts at the firewall and at the strut side, make sure they're properly tighten with zero slack.

If the above STILL did not solve your problem, then it's likely something has worn out in the camber plate. It shouldn't, but it's not out of the realm of possibility. If you still have your stock strut hats, swap them back and see if the noise goes away. If it does, then you've isolated your culprit.

The LAST possibility I would check, is check your sway-bar mount. It's not common, but it's a failure point in the E46 chassis and it is also a weak point on the E85/E86. But typically I see this sort of failure on cars with larger aftermarket sway-bars or cars track HEAVILY or both. The twisting forces of the bar literally rips the bolt out of the mount.
__________________
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
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 12:02 PM.




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