Airmatic Randomness!!
Thread Starter
Newbie
Joined: Apr 2018
Posts: 10
Likes: 0
C220 AMG Sport+ W205, GL420cdi X164
Airmatic Randomness!!
Hi All,Since owning the GL, have to say we've been really impressed with it. However recently, it seems the suspension has started to get fed up staying level. And part way through the night decides to drop but only on the front end. It doesn't always do it, and believe it or not seems to do it when parked in its normal slot on the drive. Park it outside of this or in a different orientation and it doesn't do it. When it has dropped, unlock the car open the door and it rises back up without the compressor running or the engine.I've changed the filter for the airmatic only to find the old inlet pipe had snapped so I also changed the compressor, as it seems to take an age to get to level 3, but once there it holds without the compressor continually running. I've checked for leaks and can't seem to find any. and no faults are recorded on the car or Airmatic, just an old error for the ADS N51 unit saying e Can bus message implausible, which I'm guessing is an exchange of battery.Only other thing is I changed the boot lock mechanism on the tail gate after it broke, it's electric and brought a new one from merc and fitted it myself. Not sure if its a coincidence but it's only been doing it since then.As it stands it's been sat on the drive in a different location and angle (drive is pretty flat) and it's been level and up since 17:00 yesterday.I'm lost, any ideas would be greatly appreciated. Thanks all, really not sure what to try next.
Newbie
Joined: Feb 2018
Posts: 8
Likes: 1
ML 350
Bellow leak
Hi All,Since owning the GL, have to say we've been really impressed with it. However recently, it seems the suspension has started to get fed up staying level. And part way through the night decides to drop but only on the front end. It doesn't always do it, and believe it or not seems to do it when parked in its normal slot on the drive. Park it outside of this or in a different orientation and it doesn't do it. When it has dropped, unlock the car open the door and it rises back up without the compressor running or the engine.I've changed the filter for the airmatic only to find the old inlet pipe had snapped so I also changed the compressor, as it seems to take an age to get to level 3, but once there it holds without the compressor continually running. I've checked for leaks and can't seem to find any. and no faults are recorded on the car or Airmatic, just an old error for the ADS N51 unit saying e Can bus message implausible, which I'm guessing is an exchange of battery.Only other thing is I changed the boot lock mechanism on the tail gate after it broke, it's electric and brought a new one from merc and fitted it myself. Not sure if its a coincidence but it's only been doing it since then.As it stands it's been sat on the drive in a different location and angle (drive is pretty flat) and it's been level and up since 17:00 yesterday.I'm lost, any ideas would be greatly appreciated. Thanks all, really not sure what to try next.
If the car is parked at slightest different angle the o-ring compresses and either closes or opens up depending on the angle.
Have it tested for leak or diy spray soapy water to check for leak youself.
Ns. You mention old code for U51... This is in fact the air suspension control module. Had it been my ride I would replace the suspect air spring only. It comes with all the hardware and o-rings (a dealer would try to sell you a complete strut assembly ...this is BS...dont let them.
Hope this helps.
Thread Starter
Newbie
Joined: Apr 2018
Posts: 10
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C220 AMG Sport+ W205, GL420cdi X164
Thank you for your reply, really appreciate it and is helpful. Its dropping on both sides only on the front. Unlock the car and she goes back up without the compressor or engine running, so plenty of air in the reservoir. I've had a look for leaks with soapy water and none, that of course doesn't mean there isn't one. Compressor is new, when going to off road level 3 setting it also seems slow but has been like it since I've had it.
Thank you for your reply appreciate any help you can offer
Thank you for your reply appreciate any help you can offer
Newbie
Joined: Feb 2018
Posts: 8
Likes: 1
ML 350
Bellow leak
Thank you for your reply, really appreciate it and is helpful. Its dropping on both sides only on the front. Unlock the car and she goes back up without the compressor or engine running, so plenty of air in the reservoir. I've had a look for leaks with soapy water and none, that of course doesn't mean there isn't one. Compressor is new, when going to off road level 3 setting it also seems slow but has been like it since I've had it.
Thank you for your reply appreciate any help you can offer
Thank you for your reply appreciate any help you can offer
Try measuring the amount of sag at both wheels overnight. If there is a leak on one spring only, it would put some strain on the other side causing it to sag also, but distinctively less than the leaking side. Say 40mm vs 25mm (fictitious values just for illustrative purposes).
On a recent off road trip to Botswana I destroyed my LF air shock...with no Vernier or ruler at hand, I let the ML sit for say 40 to 60min after stopping to allow the weight to shift to the working strut. Then placed twigs between wheel arch and tyre at both wheels. Sure thing, next morning the LF was snapped, but RF intact i.e. leak on LF only. On a very slow leak wait longer for weight to shift.
Anyway...my 2 cents...all the best of luck.
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
Try popping off the level sensor arm "connectors". Make sure the level arms move freely and then coat any moving parts with grease and reinstall.
It's not uncommon for the bags to get a small leak in the material that only "opens up" at certain times, based on how the bag is folded. By far, this is the most common cause of suspension drop. Try again with soapy water and spray it up real good - try and get the back side, too. Listen closely or use a mirror. Try some soapy water on the air line at the top of the strut, as well.
How long does it take to go to the fully lifted position? I don't have "numbers" - just normal and lifted modes. But it's well under a minute to get fully lifted. I can time it, if need be.
It's not uncommon for the bags to get a small leak in the material that only "opens up" at certain times, based on how the bag is folded. By far, this is the most common cause of suspension drop. Try again with soapy water and spray it up real good - try and get the back side, too. Listen closely or use a mirror. Try some soapy water on the air line at the top of the strut, as well.
How long does it take to go to the fully lifted position? I don't have "numbers" - just normal and lifted modes. But it's well under a minute to get fully lifted. I can time it, if need be.
Senior Member
Joined: Jun 2006
Posts: 375
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From: Toronto Ont Canada
GL350
If you know someone with a STAR , it will take them 5 minutes to test all bags and the leaky one will take a few more seconds to inflate, still within time and pressure range , no error code...
