Drove almost 8000 miles in the past 30 days. Sometime in the middle of that, gray "Malfunction" message showed up. Air springs don't leak. Vehicle stays leveled. I was able to raise the vehicle and lower it with a button, once. Other times I tried, compressor would start pumping and after a while I'd get message that it's cooling. Vehicle would not be raised above normal. Compressor pump would turn on every morning. And most of the time during the day when I start the engine. Pump is also louder than before.
Does it sound like a need a new air pump?

 

if you leave your truck overnight and it doesnt sag - your compressor had developed a crack in the plastic reservoir or the piston ring is worn out- anyway, you need a new compressor.

 

Truck does not sag. So, AMK (OEM?) for $350 or Arnott for almost $500?

 

Your choice. Arnott is a highly respected company.

 

I get my GL sags at the driver side only, now it does it more often, if the car is raised it does not sag. what do you think?

 

Sounds like a leaking air bag. Replace it.

 

I have no doubt in Arnott. But their pump is also made by AMK. Cost more because of warrantee?

 

Ordered a new AMK pump, for little over $300. Not from Arnott. Took the old one out, it wasn't difficult. Pump is located right under left headlight. Have to remove front part of the wheel well liner. 10mm nuts accessible from the bottom. Disconnect 2 air hoses and 2 electrical connection, remove those 3 nuts and drop it down.
There was something inside of the pump when I shook it so I decided to open it up. Some bearings fell out of there and piston had a play of about 1 mm.
It would be nice to know if we can get parts to rebuild these.

 

next time try to work the hose out instead of cutting it that hose is of specific length an shortening it may result in failure of the hose down the road- especially if old and brittle...

they do come out. with a little persuasion

 

I did not cut it.

 

you are worse than my kids... lol

 

I was actually surprised that it ripped off when I pulled on it. It didn't take much effort at all.

 

Just wanted to come back and report that after installing a new air pump, all is well. Issue has been resolved. Thank you all.

 

Our 2009 is in shop now for a new compressor, $1800 Ouch. This is after two struts being replaced. Car has 75000 miles. MD tech said it is very common occurrence.

 

1800 for a new compressor?

The part even at the MB service desk is $500 and one hour of labor ($150) for total of $650.

What planet are you on?

 

Somebody is taking advantage of you.

 

That is the quote from MB of the Woodlands

 

$458 is the list price for 1643200904 (airmatic compressor)

the book says 1 hour of labor @ typically $142-147. lets say the job gets tossed to a new tech and takes him 2 hours (i do it in 30 minutes)

what else is in the quote?

 

There was also a leaking valve that needed replacing.

 

Compressor was $575; Valve block was 557; Relay 28.28; fuse link 11.50; labor 452.88 Total $1625.16

 

sounds about right

 

Any idea what replacing struts on rear would cost? I understand that may be a little more labor intensive. Have now replaced the above and also two front struts. 75000 miles. Sure rears are next to go.

 

Speaking of relay. Should I replace mine? I have a new one but not sure if it needs to be replaced if everything is working.

 

the relay is done as cheap insurance. but if yours lasted that long i wouldnt bother- your got a good one.

some of the early ones were bad.

 

I just had a quote to replace the rear shocks on my 2008 GL450 of 1380.00 at a local tire shop. Seemed a bit high, but he said the shocks were priced through local dealer at almost 400.00 each. Price did not include air bags, which were fine.

A pair of Bilstein OE spec rear shocks on ebay is less than 500.00 with shipping. Although it is a bit of a pain to get to the upper mounts through the rear compartment, its not difficult and the entire process can be done in less than 2 hours. If you're not handy, order the shocks on-line and find a friendly independent shop to install them. Labor should be less than 300.00.