konigstiger

2003 E320 without airmatic - knocking noise heard in front end with brakes applied while turning left at slow speed.

ATTEMPTED REPAIR as documented on the invoice:

Found front sway bar link ball joints clicking with pressure applied and front thrust arm ball joints noisy when loaded. R&R all lower encap panels. R&R both front thrust arms. Replaced thrust arms and pressed in updated bushings. Replaced both front lower control arms.

331422 Guide lower cont arm/thrust/support link-both sides, R&R/repl.
331424 Bushings – (both) guide lower control arm (guide removed), repl.
1 211-330-81-07 control arm
1 211-330-82-07 control arm
1 211-330-11-11 thrust arm
1 211-330-12-11 line
4 000000-003281 nut
2 211-333-28-14 bearing

RESULT:

Experienced light knocking when turning in either direction at slow speeds – lighter than before but still there. There is a slight steering wheel shimmy and road vibration at 70 – 80 mph that was not there before. Also the car seems to require more correction on the part of the driver that did not exist before. I was told a new wheel alignment was included with the suspension repair however it is not documented on the invoice. Alignment seems to be fine in as much as the car does not drift.

As a follow-up I had the tires (which have about 2800 miles) rebalanced inclusive of road force measuring (force matching and/or computer ride matching) with the Hunter GSP9700 by Discount Tire where they were purchased. Vibration seems to disappear after tires heat up, driver correction to stay within the lane is gone, and the shimmy lessened but is nonetheless still there.

(1) What is required to bring the car back to its original tight, solid feel by removing the remaining slight steering wheel shimmy?

(2) Is it normal for the steering wheel to have play and make a knocking sound when moved from side to side while the car is stationary with the motor off?

konigstiger

So you guys are stumped also…

MB-GOD

konigstiger, without actually inspecting the vehicle those sorts of noises can be very hard to diagnose accuratly, but i can give you my initial impression.

1) For the car constantly needing steering input this could be related to the thrust arm bushing (camber links). Origionally the W211 had thrust arms that came as a complete unit but after the bushings continually failed Benz decided to make just the bushings available. Now if these bushing arent installed in the correct position it can be impossible to get the caster into spec which is a very important factor for the suspension geometry. Now even if the entire arm or the bushing was installed correctly was the wheel alignment carried out correctly? Alot of the time a wheel alignment will only consist of making sure all the toe angles and the caster can be forgotten about on a busy day because it is assumed the general Benz owner wont notice if the caster isnt in spec. I know you say you have already had this issue resolved so sorry if i went over something i didnt need to, im just not sure what you mean by the steering wheel shimmy?

2) There should be freeplay and there is a slight knock in the W211 when the engine is off, but it should only be very very slight.

As for still having slight knocks, there isnt much left to be replaced to remove suspension noised. Have the Techs rulled out the upper control arms as i have replaced them on a few occasions not on the W211 for suspension noise.

konigstiger

Thanks. Within the next week or so I’ll speak with the shop foreman. For what it’s worth he confirmed that the alignment was in spec with MB requirements when questioned. Curious as to why they didn't record the alignment on the invoice though. We also test drove the car and he claims all is within MB spec. The knocking while stationary with engine off is not “very slight” by no means. Not in my opinion. As far as the upper control arms – well we’ll see. The MBUSA SPOM was brought in from the get go and actually witnessed the original noises and instructed the shop foreman to do whatever is necessary to correct this matter to my full satisfaction – very nice fellow. Bottom line, I would rather be in the know as to what else can be done rather than going about blindly.