E-Class (W212) 2010 - 2016: E 350, E 550
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Left Front Airmatic Suspension Knocking

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Old Dec 11, 2017 | 11:55 PM
  #1  
mdreef's Avatar
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From: Houston
2020 E450 Coupe, 2022 Porsche Macan, 2001 Porsche 911
Left Front Airmatic Suspension Knocking

Folks, I need your advice on a knocking suspension noise that just started on my 2010 E550 w/ airmatic shocks. I have 80,000 miles on it, and the dealer allegedly replaced the passenger front shock earlier this year for the same reason (under extended warranty). I now have the same knocking sound but on the driver side (dealer only replaced passenger side) and I'm out of warranty. The shocks don't show any signs of leaking, and the car maintains proper height at all times. How do I know if it's a failing shock? Do failing shocks typically make a knocking sound (like a loose feeling) or should I look at other possible problems? The control arms and ball joints appear to be okay, but the shock has a torn boot, which I know causes premature failure due to dirt contamination.

I have not been able to find a source online for replacement front shocks for this car. Rear ones are easy to find, but front ones are impossible. Even Arnott doesn't have them. Is this a dealer only item?

Thanks for your help!
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Old Dec 12, 2017 | 10:15 AM
  #2  
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'71 Pinto



MB recommends replacing to current part # in pairs if mileage is 50,000 >.

“Since it can be assumed that a new Airmatic/ADS suspension strut installed in a high mileage vehicle, would not match with the used suspension strut and thus impair ride comfort and or vehicle dynamics, it is then recommended that these components be replaced in pairs only after the vehicle has reached a mileage of at least 50,000 miles (~ 80,000 km). In the cases where a strut may have been previously replaced, the mileage differential between struts must be at least 50,000 miles (~ 80,000 km) in order to replace in pairs.”

Attached bulletin references previous models nevertheless, same principle applies. Not sure how far out of EW you are or mileage when passenger side was replaced, possibly a discussion with service manager is in order.
Attached Files
File Type: pdf
32.25_19e.pdf (68.1 KB, 492 views)
File Type: pdf
Airmatic front strut.pdf (301.8 KB, 309 views)

Last edited by konigstiger; Dec 12, 2017 at 03:03 PM.
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Old Dec 12, 2017 | 02:22 PM
  #3  
cc16177's Avatar
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2011 E550
I'm curious, when do you hear the knocking sound? I may be having the same issue.
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Old Dec 12, 2017 | 02:45 PM
  #4  
Oda112's Avatar
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From: Savannah, GA
2010 W212 E550 4matic
Originally Posted by mdreef
Folks, I need your advice on a knocking suspension noise that just started on my 2010 E550 w/ airmatic shocks. I have 80,000 miles on it, and the dealer allegedly replaced the passenger front shock earlier this year for the same reason (under extended warranty). I now have the same knocking sound but on the driver side (dealer only replaced passenger side) and I'm out of warranty. The shocks don't show any signs of leaking, and the car maintains proper height at all times. How do I know if it's a failing shock? Do failing shocks typically make a knocking sound (like a loose feeling) or should I look at other possible problems? The control arms and ball joints appear to be okay, but the shock has a torn boot, which I know causes premature failure due to dirt contamination.

I have not been able to find a source online for replacement front shocks for this car. Rear ones are easy to find, but front ones are impossible. Even Arnott doesn't have them. Is this a dealer only item?

Thanks for your help!
Can you make a video with sound? I'm curious to hear what it would sound like and what sort of bumps on the road trigger it.
As for the front shocks, unfortunately, only the dealers have them. Apparently there's not enough demand for them, they don't break as often as the rear ones. They will probably start making them in the future, but for now we're stuck with OE as replacement parts.

Last edited by Oda112; Dec 12, 2017 at 02:50 PM.
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Old Dec 12, 2017 | 08:37 PM
  #5  
mdreef's Avatar
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From: Houston
2020 E450 Coupe, 2022 Porsche Macan, 2001 Porsche 911
Many thanks - I will do this! My warranty expired in April and I think I've only driven about 7,000 miles since the passenger side was replaced. I thought it was strange that they only replaced one side, as it only seems "natural" to replace them in pairs.

I thank you for the response.

Michael
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Old Dec 12, 2017 | 08:39 PM
  #6  
mdreef's Avatar
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From: Houston
2020 E450 Coupe, 2022 Porsche Macan, 2001 Porsche 911
The knocking sound is inconsistent and it doesn't do it all the time. I will try to record it and post it as requested.
I found out from dealership that it's a $1058.00 part!
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