Starting a new thread to get a more current diagnosis going.

Working on two 2009 W219 CLS 550 sedans, both owned by me. Had Arnott installed by a third party shop on the black one (color for quick reference going forward) all four corners, then I personally installed the left front on my white AMG Diamond White Edition which has the exact same part number so don't be fooled by the AMG designation. Immediately started making the same noise in the white one that the black one was making. Very evident clunking over speed bumps or slow articulation movement and a good ear can detect it at speed amongst the ambient noise. Clunking ever-present during standstill wheel lock-to-lock turning when on the ground, but not on a stand. After months of chasing, I found something that not one thread here has ever mentioned.

The lower portion of the strut assembly rotates along the length axis/centerline within the upper portion of the strut by design. I have the opportunity to compare the OEM on the right front of the white car against the Arnott on the left front. When I place a boxed end wrench on the lower mounting nut forward of the strut, meaning not on the back on the bolt head, but on the nut which is to the front, and I place rotational force to cause the lower portion of the strut to rotate along its axis, BINGO! The Arnott has a grinding, ratcheting feel and the OEM is buttery smooth.

Would like others to do this same test on jack stands to see if in fact this is found to be the case?

 

I thought my new Arnotts were clunking. It turned out to be the lower control arm ball joint that attaches to the sway bar links. They felt fine when checked on a lift, but replacement of both lower control arms has my car riding like new.

 

When you say "checked on a lift", you are indicating that the lower ball joints were hanging in an unsprung state, correct? The lift in use was a two-post, not a 4 post-drive-on lift?

If I am correct, I believe lowers (if memory serves) must be checked loaded, not hanging so that makes sense. All ball joints on both cars have passed muster by two shops and myself. Truly not ready to just start replacing parts to chase this down. Not just yet.

 

I have now checked the entire front end under both cars and I think I found something. My car has one OEM and one Arnott strut on it. The lower half of the strut rotates within its own assy when the wheel is turned. turns out, the noise is coming from the internals of the strut. I placed a boxed end wrench on the bottom mounting bolt of the strut and when I twisted the strut to emulate turning and caused the lower half to rotate within its assy, the OEM is buttery smooth and the Arnott is very "ratchety" feeling. It feels like the sound it makes when the tire is on the ground turning if that makes sense. I'm now in touch with the engineering group within Arnott. We'll se what they do.

 

Links in your post seem to be non-functional.

 

Spock to Kirk, come in!
Would you believe my new RF Arnott strut just developed this knocking noise when turning the wheel? A stethoscope placed on the upper aluminium part of the strut indicates it's coming from that area. It's quite loud inside the car. A steady knock knock knock knock as the wheel is being returned from full right lock.
Did you ever contact Arnott? My left side is ok, so far.

 

There were no links in my post. (?)

 

I did contact Arnott and they have decided to play ball. They have sent me new struts and in fact, I am installing them tonight.

I will respond back with what I find!

Sorry for the delay - for some reason this site is NOT sending me any indicator there is a response that needs to be viewed even though I am subscribed for instant notification. Will make the effort to do so manually in follow up to today.

 

I indicated that they are "non-functional". they're there all right, just getting a "not found" .

 

Thanks for the reply. I have not contacted Arnott yet, but I will next week. The noise has gotten even louder. My RF strut is a couple years older production date than my LF. My front suspension is mostly all new- upper and lower ball joints, lower control arms, thrust arms, all replaced.

Sorry about the links, they did not show on the mobile version, but now I see on my PC that they do in fact not work any more. I will remove them. They were youtube videos of my E55 at the track.

I am also not receiving email notifications and I also chose "instant notification." Pretty typical for IB's websites, they aren't the best for sure... I have saved this thread in my browser and will check back in.

 

It's definitely the new strut. I'll contact Arnott next week, I'm sure they won't have any problems sending me a replacement. I made a video for them, or anyone else interested what sound it makes:

 

Ok, an update. This front end work is a breeze and oh my, what a difference the replaced parts made. Bought this ball joint tool from amazon for $24 ( ) and the job went like clockwork. The reality is this when installing Arnott air struts. If you do NOT loosen the unibody mount bolts where the fore (Torque Strut) and aft (Spring Control Arm) lower control arms connect to the body, you risk tearing the bushings which are aged and weak (by design they are weak). As designed, the mounting bolt going through the middle of the bushing when torqued down does not allow the bushing to rotate in the body mounting brackets. It is designed that the car must be settled in its resting position, then torqued down. As such, when a shop or individual replaces the air strut, the two lower control arms have to be rotated way down to allow the old strut out and the new one in. This is catastrophic to the bushing if it is not loosened! It certainly will rotate the bushing until it tears internally, and that is where the noise has been originating in both of my W219's. I caused one, a trained MB shop tech ruined all of them on my wife's car. I replaced the struts in both cars and it did not eliminate the noise that could be heard sitting still just rotating the steering wheel from lock to lock. Went back in and replaced the lower control arms (general terminology - actual part names listed above) and viola!!!!!! NO NOISE FINALLY!!!!

The frame mount point of the control arms will look perfectly good, will hold alignment, and will not likely be found using a microphone. I've been down this road with two dealers and two independent shops, and I've spent over $500 in labor between them all and they all threw up their hands...sadly. Again, this all came to light when I installed my own new strut, and immediately I had the same noise in the left front of my car as on both sides of my wife's car. I am so tickled. Questions?

 

Mine are doing the exact same thing, sounds awful in the cabin. Arnott refused warranty cause I can't produce the receipt. So much for lifetime warranty..

 

anyone ever try RMT struts?

 

Does anyone know if an E55 front strut with be the same as a CLS55 strut?

 

So I've definitely come to the conclusion that these Arnott struts are clunking on the inside, and it seems to be coming from the upper portion where the air cylinder is. An internet search seems to reveal that this is a very common issue with these particular struts over a wide variety of different platforms. I confirmed that it's definitely coming from the internals of the shock by jacking the car up and having my son turn the steering wheel left to right. You can physically feel the internals of the upper silver portion of the strut clunking and banging as you turn the wheel. The noise cannot be coming from anywhere else in the suspension as it is completely unloaded and every single other component on the suspension is brand new. Is very disheartening to know that this aftermarket company knows about this issue and does very little to address it. I can tell you these struts do not have many miles on them and are in almost new looking condition. This is a serious defect by the manufacturer in which they denied me warranty coverage.

 

I feel really bad that I haven't updated my original post with my very expensive endeavor. Here is the short, short version of what actually transpired over an additional four months after my update within this thread (Dated 6-4-2020).

Folks - the Arnott FRONT struts that are brand new as well as the remanufactured units are noise makers, period! It's an internal design flaw. These Airmatic Struts were for the front of my CLS AMG W219 2008 models, as a refresher to my opening post. That these make noise is no less than fact. I know how brash that sounds, but please read on. I would be happy if I only spare one other human the OCD pursuit I have been on. And I saw it through, for the record.

I ultimately installed 9 front struts over the course of 6+ months, both new and remanned and I pushed on Arnott Customer Service and their Management team until I got to a 30+ year tenured engineer (if they and he were truthful with me) and it's simply a statement-in-fact, a data-driven fact, their internal component design creates noise that sounds like a loose strut at the strut tower, or, like worn out drop links. To keep it simple so that you know this is not just one idiot voicing a self-aggrandizing opinion, know this; I ended up replacing every single part of my front end on two CLS' sans the rack-and-pinion, only to have the "knocking" and "thunking" noise resurface after each new strut from Arnott was installed. The engineer and I were just not willing to accept that it was a design flaw, we suspected a manufacturing QC issue, but after 9 struts, both new and remained, the conclusion was unavoidable.

After absolute exasperation set in, I got a hair up my back end one morning and went and bought a brand new OEM strut (not MB OEM Remanned - more on this momentarily) and installed it and immediately the noise was gone on that side of the car (just like with the Arnott units), BUT it never returned. Two weeks later, I figured I was good and had finally found the smoking gun, I replaced the other front brand new noise making front Arnott strut with another MB OEM strut, this one remanufactured from MB, and my car is as quiet as it's ever been and remains so. I'm 30K miles later and no front-end noise! And just to put an exclamation mark on this, I paid for 6 of the 17 alignments performed after chasing ball joints, control arms, and strut changes to ensure that alignment geometry was not a participant in the noises. The longest my Arnott struts went before they started knocking was three days, the norm was the next day. I would do a test drive with the newly installed Arnott and the car would be silent (and I would smile thinking the false gold was real), but within a day to three days, the noise was back. Every. Single. Time. Two OEM front struts later, no noise whatsoever. Period.

Feel free to mock or disagree, but I think we can conclude that 9 struts replaced over the better part of a year constitute an issue that isn't just a QC issue. Further, I have now replaced my rear original Airmatics, and I have some very cautionary advice to help anyone who asks. In simple terms, the Arnott rears make no noise, but they abandoned the supplementary air reservoir that provides very detectable and important reserve air volume for a ride that the MB is known for and that you paid for. The Arnotts work, but they are inferior in performance, to the point, even my wife who is NOT a car person, said to me, "I don't like the way the back of my car rides now" after we installed the Arnott's on the rear. I went with the OEM on my car, the same year, same model, and same suspension, and the difference is very much superior to the Arnott design. I also devised a way to install them without disassembling the entire rear subframe. IT CAN BE DONE!

I am not an Arnott hater, for the record, but I do think they should own their issue on the front strut design and I also think the majority of MB owners will never be the wiser on the Arnott rear design and performance deficiency.

 

Great information and I 100% agree with reman struts. I got RMT and they are making slight noise also. Not nearly as bad as the Arnotts however.Guess I either need to spend the money on mew OEM struts or making my exhaust louder..😬

 

You are supposed to disassemble the entire rear subframe to change the air springs?? Really??

 

holy sh*t I literally just dropped off my 04 E55 at the shop that installed new Arnotts earlier this year… for the same clunking noise you describe.

I thought it might be a defective strut and that I could have it replaced under the lifetime warranty.

Wish I knew this before I paid for the arnotts and installation back in February.

I’m seriously considering replacing all four arnotts with the bilsteins because the car rides and sounds like a slammed civic.

 

Does anyone know where f you replaced the air ride with a coilovers set up, is the dash gonna display some codes for the air suspension? If so what a there a fix to get around this?

 

I told my wife I am seriously considering offering to do air suspension repairs, along with the full array of fluids, and regular maintenance amongst other things for MB and BMW owners. I've caught the dealers pulling ****, I've caught the sole proprietors red-faced, red-handed not doing it the right way, And now I do it all myself. I am now sporting the quietest car - it's back to the way it was originally. I have also cracked the code on the rear shocks. Also, wait until you do what I did and literally go through alignments in the teens, can't recall for sure but it was over 14 alignments only to find out they were not trained in setting caster! Had two shops try to tell me my chassis was bent - car has never had any bent sheet metal. Went to two frame shops because I was beginning to wonder. Even one of the OEM MB dealers here couldn't adjust the castor! THIS IS NOT FICTION. I was going CRAZY. You guys want a quiet ride, send your car to me, ha! I've bought so many parts from the dealer, I am getting a discount on OEM parts. The Bilstiens are probably a great alternative but until I hear someone say they don't thunk, I won't use them. FCP Euro is a great resource, but one must have the tools. I've two lifts in my garage, and I just went through this with an E550 Sedan with the Sport package and he is over the top happy! Getting ready to do his serpentine, thermostat, oil cooler gasket, and all of the fluids. I bought all of the equipment because I got tired of my car coming home with "production shop" damage to my wheels, interior, etc. The Dealers don't know what many of us have learned because they don't generally see the older cars. I call the OEM Dealers a 1st tier owner production repair shop, maybe a 2nd tier owner repair shop if there was an extended warranty. That leaves the knucklehead shops. I can tell you stories. My wife's HID system went to the dealer time after time for dim HID's. After I cracked open the $1200 headlight assembly by baking it in the oven and detaching the clear lense, I found this: if you self-select HID's to also be your daytime running lights via the dash options, turns out you will burn the reflective coating off of the projector reflector! They turned up the voltage, replaced the bulbs, and I bought brighter bulbs. Driving it at night was nearly blind driving. When I showed them, they had no idea HID's would do that to the projector - the voltage and everything else was working perfectly, the reflector just had 100K miles of always being on and it finally burned through all of the metal coating on the reflector. Just one example. If you get your front end sorted, be advised, the rear shock absorbers will also knock. They'll perform damping and rebound just fine, but when they have just a tiny bit of fluid evaporate out of them, they will thunk and make you think the shock absorber is loose at the tower in the trunk. Not the case.

 

Wait, I thought the Bilstiens we're the ones you used? Arnotts make noise so which struts are the best to use for a quiet ride?

 

After months of being annoyed with a weird suspension noise and replacing basically the entire front suspension except for the sway bars and upper control arms.I replaced struts, lower front and rear control arms, every ball joint, sway bars endlinks, steering rack bushings,inner and outer tie rods and new Bilstein struts. Thank God I do all my own labor and the parts aren't terrible expensive except the struts, which I needed anyway.
I finally think I found the culprit of my noise...It seems like it's either the actual rack, the column or most likely the steering coupler. I just ordered the coupler since it's the cheapest part and it feels like there is play in it. The one weird thing is once the car is running and the rack is pressurized I don't hear it from the steering wheel test. I guess I'll do the coupler first and see from there. The car was in a minor accident many years ago according to the Carfax.
https://youtube.com/shorts/pIw1-ZfhWAQ?feature=share

https://youtube.com/shorts/IBAwJuNhL7k?feature=share

 

I know that this thread is a bit old, but I have had, and still have, this problem with my '06 E500. I called Arnott this week and provided a video and recording of the noise. This is what I got back from their tech support:

We received the following message back from the Head Engineer in R & D.

This is caused by the suspension geometry and how the lower control arm swings fore and aft with the steering movement imposing a slight twisting on the strut assembly. The OE sleeves are thin and can accommodate this twist. In short, the popping sound is not common with the OE assemblies because the OE sleeve accommodates the twist, where ours doesn’t.

Unfortunately, there’s no update or fix for the popping sound since all of the Arnott air shocks have the same sleeve.

So that is the official answer. After all of these years, one would assume they would have found an answer.