Weird Airmatic Issue
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Junior Member
Joined: Jul 2015
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ML550
Weird Airmatic Issue
Hi, I'm hoping someone can shed a light on my issue. My front drivers side airbag lowers down, but not all the time. I replaced the sensor inside the wheel well (but with a cheap Chinese knock off part) and the problem persists. I can drive it and the shocks stays pumped up, park it sometimes for days on end and it stays pumped and then some says although it p[umps up and drives fine when I shut it off it drains out the bottom of the bag, I can both hear it and feel it coming out. Am I missing something? Seems like a sensor issue not a leaking bag.
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Joined: Aug 2016
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From: Chennai, India
ML 350, Punch AMT Creative, Prior: Maruti-Suzuki Esteem LXi, FIAT 1100D, Studebaker Champion
Possible problems based upon your description of symptoms:
1) Sensor faulty (your initial diagnosis may be right - you could check this if you have a scanner and use it to study the individual sensor readings at each wheel.
2) Leaking airbag (try a soap water coating and look for air-bubbles)
3) Leaking airline/grommet (try a soap water coating and look for air-bubbles)
4) Faulty Valve body (tough to detect, the valve body supplies air to each of the airbags and it may be allowing air to escape from one airbag. One way to check this is to interchange the front L & R outlet connections from the valve body and see whether the problem has shifted from the drivers side to the passenger side.)
Good luck - Trust this helps.
1) Sensor faulty (your initial diagnosis may be right - you could check this if you have a scanner and use it to study the individual sensor readings at each wheel.
2) Leaking airbag (try a soap water coating and look for air-bubbles)
3) Leaking airline/grommet (try a soap water coating and look for air-bubbles)
4) Faulty Valve body (tough to detect, the valve body supplies air to each of the airbags and it may be allowing air to escape from one airbag. One way to check this is to interchange the front L & R outlet connections from the valve body and see whether the problem has shifted from the drivers side to the passenger side.)
Good luck - Trust this helps.
Thread Starter
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ML550
Thanks NRR, I did find that the air is coming out of the bottom of the bladder / bag whatever you call it. But I think that's where it is supposed to bleed out of when it lowers etc. Am I correct? also what's the thing all the lines join into behind the front bumper on the passenger side?
Newbie
Joined: Aug 2016
Posts: 13
Likes: 0
From: Chennai, India
ML 350, Punch AMT Creative, Prior: Maruti-Suzuki Esteem LXi, FIAT 1100D, Studebaker Champion
No, there should be no leak from the bottom of the airbag(airspring/bellows), this would indicate that there is a cut at the bottom, you could have the airbag(airspring/bellows) inspected at an Indy shop and if cut then only the airbag(airspring/bellows) requires replacement. Fairly straightforward process.
Since you asked, perhaps I may add some information about how the air pressure is controlled in the airbag(airspring/bellows). There is a compressor, air reservoir and a valve body (which you located behind the front bumper. Air pressure is maintained by the valve body which will allow air from/into the air reservoir which stores air at pressure. Whenever the pressure needs to be built up again the valve body releases air from the reservoir into the airbag(airspring/bellows) and the compressor will replenish the air in the air reservoir.
Good luck - do share the solution with us once completed
Since you asked, perhaps I may add some information about how the air pressure is controlled in the airbag(airspring/bellows). There is a compressor, air reservoir and a valve body (which you located behind the front bumper. Air pressure is maintained by the valve body which will allow air from/into the air reservoir which stores air at pressure. Whenever the pressure needs to be built up again the valve body releases air from the reservoir into the airbag(airspring/bellows) and the compressor will replenish the air in the air reservoir.
Good luck - do share the solution with us once completed
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Joined: Nov 2015
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ML550 2008
Mine did the same and I thought due to the inconsistent nature of it leaking out some days and being fine for days it was something besides a leak. In the end it was the airbag that needed to be replaced. Replaced mine 6 months ago and no more issues.
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ML550
Thanks for the replies. I suspected as much, my indy guy replaced the passenger side last year when it exploded in the heat. He said it might be a good idea to do both but since it wasn't leaking....
Looks like I'm in for a new bag.
Looks like I'm in for a new bag.
