I was driving my W221 2012 to work this morning and half way down the drive, the rear suspension on both wheels collapsed and on the dashboard I got Malfunction message with suspension icon (car with an up arrow). It has been fine up to that point and no such issues. Now I drove the car to office in a very unpleasant and bumpy ride.
Its now sitting here with both rear wheel suspension totally collapsed. The front wheels are fine. I don't hear the compressor running. Its all of the a sudden so I don't think both rear air bags exploded or something at the same time.

Is there any thing I can do at this point. Any reset, or anything I can try.
P.S. The compressor/pump isn't running and that may have caused the rear suspension to collapse. What can I check? i.e the Fuse relay location of the compressor/pump or could it be the height sensors are gone? I tried raising the suspension to max with that car arrow button thing but couldn't hear the pump whirring.

 

$35 for the part - 100% normal feature of owning a 221 - the failure is a fragile headlamp level sensor link rod Merc chose to use on a Safety critical suspension level sensor - the black plastic bits seize on the steel ***** of its ball and socket joint - and the fragile bracket slowly snaps more and more of its fastening elements, till it falls off and the car tries to kill you

enjoy the fight refitting the new one - and ask a lawyer to get the criminals at Merc locked up for deliberately making the car fail dangerous - if we pretend it wasn't intentional, lets say 3 years to update the software so it stayed safe after it snaps off - so what’s the other 15 years been about - laughing at the death and misery they deliberately left in play -

top tips

1) its hiding above the park brake module and its impossible to see let alone reach
2) forget trying the impossible of snapping this on to the anti-roll bar - and use a stainless steel worm drive clip after locating the flat on the ARB so its in the correct place....
3) using the clip installation method a competent garage should charge you 45 mins - but some will want 6hrs labour to mess it right up and do it all wrong
4) you have another two (three in total) at the top of each front wheel, trying to snap off too

 

@BOTUS Thanks for replying. I was beginning to think this website/forum was inactive.
It seems you are pretty certain of the underlying cause of the issue ( and I don't doubt it as I have no idea wtf happened all the sudden!) And also that it is not a DIY friendly task to refit the level sensor.
I was able to drive the car back home very gently and slowly with flat rear suspension but my ***** still hurt from all that bouncing in the car. And come tomorrow morning, was going to take out my Snap-On Modis Ultra scanner to scan for any codes. And also try to check the Airmatic fuse etc. under the hood tomorrow (even though I have never done car fuses or relays before). So are you suggesting that this troubleshooting isn't likely to rectify the issue and a trip to the garage is due?

 

jack left side rear up - with a bright torch, in line with mid wheel height, in front of the rear tyre - look in about 30 inches - you should see that bit in the photo hanging off - it mounts on the ARB

be aware NOTHING supports air tragic suspension - significant risk of death as it will collapse on you (as no real springs to support the weight), with the road wheel off - I was able to reattach what was left of the bracket using a worm drive clip and the car goes back to normal upon start up where you can get it on a ramp and fight the utter insanity and attach the new link rod...

the fronts will be almost as bad and use a similar but different part numbered bit - and are far easier to replace at home


.

 

@Botus: you were 100% correct. It was indeed the rear height sensor link rod (fitting rod) that had corroded due to rust and broke down leaving the rear height sensor dangling, which in turn seized the whole Airmatic suspension i.e. the rear airbags were totally bled out instantly, the compressor will no longer run and all that horrible stuff!

Unfortunately I didn't have the luxury of time to diagnose this myself as I was just about able to drive the car back home from office. I used my scanner and it came up with fault code 5283 (recovery time too long during filling of central reservoir.. obviously as the compressor wasn't running), along with a couple of other codes ( I think 5286 (recovery time too long after bleeding of air struts) and 5282 (Critical vehicle level front right... I guess this is since the front height sensors were still working as they should) and there was mixed response to this error code 5283 when I looked it up on the Internet with most saying the compressor is busted. So I just didn't really have the luxury of trial and error that you do if its something you can live with for a while. The rear suspension was totally flat so the car was almost at ground level at the rear. Before this issue occurred, I did have another issue where the car would start to sink in all four corners after being parked overnight and would continue to lower over extended duration (I suspect the airbags were losing pressure for some reason) and I was told by previous owner it was normal and nothing to worry. Well I was naive to believe it then but thought I could live with it as the compressor would run when I would start the car and inflate the airbags to bring it back up. SO, my front struts which didn't deflate fully like the rear ones after the link rod crumbled were slowly losing their pressure as well, as just explained. It was the long weekend in UK and I called the Mercedes Benz specialist garage and they said to bring it in after the long weekend i.e five days later. I just had about enough height left in the front to very carefully and slowly drive the car to the garage on the day. Otherwise it would have been a tow truck job.

So I was sent an invoice of over £500 for the work. Diagnosis £120, fitting rod part £25, Labour £360.

Then I re-read your post that there are two more of these link rods waiting to fail in the front. I asked the garage to get those changed too. They were saying that they are fine but I just didn't want this horrible experience again so they are going to change those too. On top of that they said that the front left air spring link is rusted and needs a change (the previous owner had replaced the front right air spring link). So I agreed. This added abut £650 to the bill (parts and labour) meaning I have to foot a bill of around £1150.

Well I couldn't avoid the garage bill but I hope this helps others! Especially if they can do some preventative maintenance.

 

And now it is good for another 10 years😊

That “Recovery time too long” does not mean the compressor is bad. It mesns the car shut the compressor down so it won’t burn itself to pieces. This is to protect it.