Slow leak in rear Airmatic 2009 GL550
Thread Starter
Junior Member
Joined: Aug 2016
Posts: 18
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2010 S550; 2009 GL550
Slow leak in rear Airmatic 2009 GL550
So we have replaced both front airmatic shocks PLUS the compressor. Now we are getting sporadic leak-off in both back shocks, sometimes both leak off, other times just left rear leaks off. Sometimes they will leak-off very low but leaving about an inch of clearance above the tire, other times 2-3 inches vs the normal 4-5" clearance. They will some times go weeks without the issue. Any suggestions on why they are acting this way? I am thinking the airmatic shocks are slowly failing, and as eluded to in other discussions could put an undue stress on the compressor. But why would both go bad simultaneously? The fronts went months apart. Note also that the leak off never occurs when vehicle is in use, only after stopping for periods of time, sometimes 2-3 days other times an hour.
Thanks all.
Thanks all.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,762
Likes: 630
From: Emmett, ID, USA
2007 GL450
The bags have a modest lifetime. Just replace them. Aftermarket (e.g. Arnott) don't seem to be much more reliable, but they are cheaper than OEM and have a lifetime no-hassle guarantee.
Replace the rear bags before they over-stress your new compressor. They're even easier to replace than the front.
Also, I recommend not replacing the line fittings despite Arnott's instructions to do so. It saves time, and replacing them adds to the risk of things going wrong during installation.
Thread Starter
Junior Member
Joined: Aug 2016
Posts: 18
Likes: 0
2010 S550; 2009 GL550
Thanks Eric, I watched a video link from Arnott and it even looks like a caveman could do it. In case I cant find my inner caveman, what would you guess that a dealer would charge per side? The Arnotts are $180. My guess is OEM are probably $300. It only took the guy on the video maybe 10 mins total with part of that disconnecting compressor fuse, raising the vehicle, and removing the tire.
What are the chances the shocks need replacing at the same time in your opinion? Thanks again.
What are the chances the shocks need replacing at the same time in your opinion? Thanks again.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,762
Likes: 630
From: Emmett, ID, USA
2007 GL450
Rear shocks are almost completely separate from the air spring. Shocks last ~80k miles. It would hardly hurt to change them earlier, because they progressively degenerate.
