stevebez

OK spoke to my tech yesterday about this and the rear suspension "air bags" at the rear only have locator knobs and are NOT secured to the chassis. So if you wnat to get rid of this noise I suggest you get some proper flexible adhesive in between the bag and the chassis. I found this fabulous glue that is just rediculously strong AND flexible... anyway I digress. I'll post up the name later if anyone is interested. BTW I have not bonded my bags as I seldom go over bumps and I go super slow anyway also it will be a major PITA DIY job which I dont really have the stomach for just now. The thump is defintely worse in the cold though FWIW.

There is no fix for this other then bonding the bags to the chassis.... and if you think you ever need to replace the bags please dont bond them to the chassis...

GT-ER

Hmmmm....I'm currently working something out to gain access to Star Diagnosis. If I can get my hands on one then I'm just going to swap for a coil suspension. I've asked around people who have ridden in Airmatic vehicles and they have told me that they too have heard the thump in the trunk...no good imo and just down right sad on a $100K car.

redlineAMG

I have this problem and I have purchased new rear shocks to get rid of it. Now the only reason I would spend big bucks on rear shocks is the fact that I replaced the rears on a 03 E320 with airmatic and it had the same noise before and it was gone afterward. As soon as I install I will confirm elimination of the noise.

GT-ER

Please do and let me know. Also, when you remove the rears please tell me if you can tell there is something wrong with them when you remove them ( try to compress them by hand ).

0700700

Hi. I have had this problem since the car was 19000km old. No noise , and suddenly it started clunking, and it got worse and worse and worse!!!...

Now it clunks like something's gonna break


I checked and rechecked the inside of the trunk, the battery and everything. Then i got the shocks replaced and the problem was still there, so next thing i replaced the bottom mounts and the rubber things on top of the shocks, and its still there...


Now car is outta warranty so im pretty much pi$$ed off MB service couldnt resolve it. My service rep says its the shocks again but i have a sneeking suspicion that its eiter the rear airbags (or whatever they are called) or the rear axle mounts.


I have bought the rear axle mounts but frankly am scared to commit to a rear axle removal so clunk is still there...

socketman

Its the rear shocks I played chase the noise on a customers car replaced a number of parts I didnt think it was the shocks due to still having god rebound but thats what fixed the noise.

GT-ER

Crap!!! what to do...what to do....LOL.

When you took the old shocks off, did they feel okay? Could you compress them without any noises?

0700700

yes they felt fine there was a slight movement in the top part of the shock assembly, the vertical movement and compression of the shocks was ok though. Let us know how you sort yours out

GT-ER

I think I'm just going to bite the bullet and get the shocks and see what happens. If they do not solve the problem then I am 100% going to convert to coil springs. I love how the airmatic system feels, but it's complexity/cost it really not worth it.

GT-ER

Well, I did it. I bought two rear shocks from aboveallmotorwerks.com for $840 shipped ( I live in PR and they were the cheapest shipped I could find ).

Lycan

I have been experiencing a thunk when slowing down from a take off. Is this the same thing? As i slow i occasionally feel and hear this clunk or thump. Is it the LSD? Are we talking about the same issue?

jamcclureuk

I had the same issue. The dealer replaced both airmatic shocks and the noise is gone.

Lycan

So was the thunk noise the shocks?

GT-ER

My clunk only happens when going over speedbumps.

I have my new shocks here with me, I'm picking the car up tomorrow and should be installing them later at night ( very simple job ).

GT-ER

EDIT: Noise is definitely still there. The rear shocks DID NOT solve my problem. It's gotta be the air springs and I'm not going to even bother replacing them so my car stays as is until I get the money to just convert it to a coil setup.

0700700

hey. i dont wanna sound rude, but are you sure they REALLY replaced your shocks? Cause in my country the sneeky b@stards have been known to replace the outer dust boot of the shock, thus giving it a "new" look, while selling the shock to someone else

Im not sure it applies to your case , but if you can inspect the bottom mount of the shock... where it attaches to the suspension, it should be nice and shiny.


But overall, i think i warned you its not the shocks its either the rear axle mounts or the air bag-thingies...

As for a conversion to a coil-over setup, i have also pondered upot this, even looking at the CLS350 parts, but was told that
A) the car would not be able to keep equal clearance on all four corners
B) The computer would go crazy if the air suspension system is deactivated.


You can always speak to brabus, that have designed a convetional system for their brabus rocket... But the price of conversion is around $12k... so not worth it... Just let it clunk

GT-ER

I replaced the shocks myself so I'm sure they are new.

I'm pretty sure you are correct on it being the airbags though....but like you said....I think I'll just let it clunk...lol.

0700700

well let us know how it works out, assuming of course you want to spend another 2K on the air bags.. Also check the air suspension piping on the rear axle, maybe a large compression will reveal a leak somewhere... Kinda off-topic but my 7 series has air suspension at the rear and left shock was dropping real fast.. turned out a small stone had blocked the pipe so air supply was limited.


If you are car savvy, checking out the rear axle mounts might be the cheaper alternative..


Whatever happens, please update the thread if you find anything else

Lycan

I talked to my local MB dealership and they asked me to swing by and take out a Master Tech to hear it. The problem is that it only happens once in a blue moon. It's either the LSD or the shocks. My vote is the LSD---on my car at least.

saleen01

hey guys, ive recently started experiencing a bottoming-out kind of clunk on the pass. rear when i go over potholes...but only at normal driving speed, nothing slow and over speed bumps...anyone have this symptom?

rtc55

I had the same problem and mine ended up being the rear shock.

GT-ER

The clunk I have is when the car slowly goes up and down, like after getting a speedbump at a slow speed. Mine is definitely the air springs. The one you are describing sounds like a shock absorber.

saleen01

thanks, am i ok to replace only 1 shock ?

GT-ER

Yes, although most would argue that shocks should be replaced in pairs ( which I can agree with ).

saleen01

haha...nice, i was afraid you'd say that...900.00, hows the install?