GL 350 front air suspension
 

The front suspension on my 2011 GL 350 appears to be fully compressed when left overnight. Once started, it raises to normal ride height and will maintain that position throughout the day. I suspect a leak though none is visible. Is there anything else I should be considering?
The car has just short of 70,000 miles.
If this is the correct diagnosis, what am i going to be looking at for parts/labour at a private shop. I live in southern california.
Thanks

If both fronts are down you might have a leaky valve block. A leaky shock usually has that side very low and the other a bit higher.

MB air suspension is notorious for developing leaks at about 70-80k or about 5 years in service. It happens on all airmatic equipped cars so don't feel bad about your GL. From my personal experience it's best to change both air shocks at the same time as they tend to fail very close to each other. Don't go through a dealer to get new air shocks since they are very expensive. There is a good supplier called ARNOTT https://www.arnottindustries.com that rebuilds these with much better parts and sells them with lifetime warranty. I've had them installed on my E500 and GL450 and haven't had any issues.

Don't drive with failed shocks for too longs since it will wear out air compressor and will be more expensive to fix in the long run.

Where is So.Cal are you? I may be able to point you to the local indy shop who can do it for you.

I second Arnott. I went through two sets of MB airbags at all four corners but the Arnott's seem to be holding strong with none of them replaced. If I still have the same Arnott airbags at 250k miles, it will prove they are a much superior product than the factory airbags.

Same thing just happened on mine, the driver side front would occasionally be down. Was sure it was not the shock. Decided to replace it with Arnott and for the last few days I haven't had the issue.

I'll add one other word of advice, replace the whole assembly. It might be a little more expensive, but the struts don't last forever AND the job is much, much easier. I replaced (myself) the air springs at ~60k miles. When we got close to 85k miles (about a year later) the vehicle was a little "floaty" and we would occasionally here a popping noises. Arnott was very helpful and even provided s substantial discount on the whole assemblies to me since I purchased the air springs from them.

Gentlemen;
Thank you for the advice.

I replaced both passenger side bags. Bought both rear bag and front reman strut/bag from RebuildMasterTech.

Other than NO instructions included they went I easily with no prior experience in the job and it took 3 hours total.

Other than some weird intermittent air manifold issues the two airbags have been faultless. $350 for one front and one rear.

Reviving an old thread here as I need to know exactly what happened if I did not disconnect the Level sensor plug. I have a 2010 GL350 and the setup is different. I cannot find the plug behind wall fender well liner indicated in the Arnnot video.
The attached instruction clearly indicates to "Disassemble the level control sensor rod" instead of the plug.
Anybody can tell me which is the correct way to do it? and in case of the "sensor rod", what will happen if I do not "Disassemble the level control sensor rod"? Any possible damage to the level sensor unit?

I have separated the upper steering triangle without disassembling the level control sensor rod or disconnecting the level sensor plug and worried if I have damaged the level sensor already. The upper steering triangle just went up after the separation by itself. Anyone can let me know because I am concerned that I may need to change the sensor assembly if I damaged it.