Nessco

Hi.

My rear end can lower itself all the way down after 1 night if i was out driving the same day, while it can be on normal level for weeks does not matter if i was driving or was on vacation and it was standing in the garage for 2-3 weeks.

Why is this happening?

Is it normal, is something wrong? no idea 🤷🏻‍♂️

Thanks for any input.

Rehabguy

I the rear of your car bottoms out, regardless of the amount of time parked, there is a problem. There's gotta be a leak somewhere.

Nessco

Something a diagnostic can show or is it only something mechanic can do searching for leakage etc?
My guess its some kind of valve?.. since if there is a hole or damage in the air cushions it would be lowered down always when not driving..

Rehabguy

I don't think that a diagnostic tool could tell you where the leak is, especially if you don't have a fault code. Would be prudent to scan either way. It is a common issue for the air springs to go bad. It's not something you wanna hold off on fixing. If you have a leak somewhere, the compressor could be working over time to keep the rear end aired up and in time, prematurely kill itself.
Take a look at this page and see if it could help.
MBMedic Air Suspension
Good luck resolving the issue.

Arrie

Do this simple test. Leave car in COMFORT setting and observe level next morning.

Then do the same with SPORT setting.

See if there is a different result.

Nessco

I always drive in comfort mode, very rarely activate the sport mode when driving. for max 5min and turn it of again while driving.
Why should that have any effect? 🤔

konigstiger

Sedan, wagon provide VIN. Sedan, check both rear air springs & valve unit for leaks and overall condition. Depending on time elapsed, mileage, and repeated harsh weather conditions if valve unit seems fine with no leaks most likely air springs are beginning to fail internally requiring replacement.

Nessco

I always drive in comfort mode, very rarely activate the sport mode when driving. for max 5min and turn it of again while driving.
Why should that have any effect? 🤔

Nessco

HiThanks for the instructions
VIN: WDD2122011B331718
310.000 km on the clock

Nessco

.. wagon

konigstiger

Wagon, air suspension in rear only same initial leak tests @ air springs & valve unit. All looks good have someone pull fault codes using Xentry (MB diagnostics), included additional CU & electronics info for future reference.

konigstiger

Simple method to to check if one or both rear air springs are malfunctioning internally - internal air chamber & valves.

cvx5832

tl;dr same symptoms on mine. Sometimes it would leak, sometimes it would hold air. Happened intermittently until I swapped the bags out with the Arnott units popular here. E63 if that matters.

Long version, start checking the VOSS fittings. Super cheap and easy enough to swap. I noticed the o-rings inside them (x2) get hard like every other rubber on the planet. Given that the air line probably bobs up and down during use, how it ultimately settles when you park can determine whether it leaks or holds air in the next 12 hours.

But if you're a buy once, cry once type of guy like I am, just swap the bags since they also take a set and get hard like, you guessed it, every piece of rubber that gets old.

Nessco

Thanks 🙏 a lot for that explanation too .. will check it asap for leeks

up_too_late

I had similar symptoms on my '15 wagon. It's a common opinion here that the rubber "ages out" vs wearing out due to mileage. I took a leap of faith and changed out the rear airbags with Arnott's and haven't had an issue since. Comprehensive post of tips here: https://mbworld.org/forums/e-class-w...r-springs.html

Left Coast Geek

note that with the rear only airbags on a wagon, the E vs S mode switch has no effect, E vs S mode is strictly about transmission gear choices. AFAIK, there's no 'comfort' setting on a E350 wagon (certainly isn't one on my 2016).

Raj1471

What is the mileage on your vehicle and have the air bags ever been replaced? My 2011 wagon started losing air from the left rear air bag around the 90k mile mark. I replaced both rear air bags ( I figured replacing the right rear was prudent while I had the vehicle up on jack stands and avoid having to muck about with the right side at a later date when it eventually will start to leak) with the Arnotts and solved my problem. There might also be the possibility of a leaky valve block but I think the part that gets the most wear and tear is the air bag itself. Easy to check if you have a leaky valve block by spraying some soapy water on the valve block and looking for bubble formation indicating a leak. There are lots of videos on YouTube and step by step procedures on this site if you decide to tackle the job yourself.

Fred2

What would be the most likely cause for both sides to droop at random times?

After putting it away for the night, I notice that some mornings it is fine, and others it looks "slammed"

Ppanko01

Gl450 x166… rear suspension lowering once in a while. Some days a couple times in a day and other days no issue. Wired, car can hold level overnight but then you drive for 10-15 minutes, park it at the supermarket, get back 30-45 minutes later and rear collapses. Start car, raises rear and all good again. Get back home park overnight and still good … go to store next day and same thing happens. Any ideas what would cause this? I replaced airbags 3-4 years ago with OEM, replaced shocks absorbers, compressor is 3-4 years old.

Left Coast Geek

This is the E class (w212) forum, you probably want to find the 166 section to post in... while I'm sure the airmatic systems have much in common, there's often chassis specific details.

Ppanko01

Already posted in x166 forum. Looking for any similar issues or fixes regardless of chassis … Airmatic sys not the same … understood… but quite similar in function regardless of model.

Left Coast Geek

Is this self leveling rear only, or is this the full dynamic ride system with comfort vs sport settings ? The 212's come with both, the wagons have the rear only self leveling airmatic, while the V8 sedans and AMG cars usually have the full 4 wheel airmatic with dynamic shocks.

Ppanko01

It is 4 Airmatic … self leveling system. Wonder what could cause rear suspension to collapse once in a while assuming no air leak at the airbags.

Left Coast Geek

well, if its not leaking in the airbags, then either the plumbing, or the control valves, or the compressor is leaking.

Ppanko01

if it is a leak …would it be consistent? Why isn’t it go down overnight? I’m not after driving it.