After further investigation and diagnosis it's probably either this or the compressor. Managed to catch the car dropping today and was able to get to the shop to scan for codes. Cancelled my air spring order for now while I wait back to hear the verdict.

 

Over the past 4-6 weeks, I have thought that my car was not sitting correctly or was leaning to the side. After arriving home last week, I discovered that my passenger front was sitting much lower than the other side. However, I did not have any dash warnings. I was able to raise it, then re-lower and it sat fine. Today I took the car out and the same corner sagged the entire time I was out, but still had no dash warnings. So, what do you guys think? Strut or valve block? The driver's front strut was replaced ~20 months ago.

 

Check the pressures with STAR. Put the car in "raised mode" and pressure the strut via the diagnostics. It's apparent when it's leaking because it doesn't hold the same values as the other side.

 

I think I had multiple issues going on with the Airmatic. This week I replaced (rather, I paid the shop to replace) the compressor, relay, valve block, and some miscellaneous filters/hoses in the system. After almost 12 years it was probably time anyway. A little under $1200 out the door.

The good thing is, I think this fixed the intermittent white warning light that was coming on sometimes on the MFD. This warning came on periodically over the past 2 years, but there were never any issues associated with it so it was not addressed as the shop told me it probably wasn't worth the time or money until there was a problem. The code read with the Star diagnostic indicated that the compressor was not pressurizing as quickly as expected. So it seems to me that it is likely that my compressor had been slowly going out for quite some time.

The bad news is that this did not fix my intermittent sagging in the rear. The car still, apparently randomly, drops on the driver's side rear. Sometimes it seems to hold pressure just fine overnight but as soon as I start driving it I can feel the car pull to the right, which I'm sure is great for the $1,000 tires. Pulling over verifies that this is pulling because the rear is dropping. Then again it sometimes runs perfectly and drives straight as an arrow.

Any ideas on what else this issue could be before I bite the bullet and replace the air springs? Rear level sensor maybe? The mechanic said that based on visual inspection the rear air springs looked almost brand new, and the level sensor did not throw any codes. Also, most of what I have read and what the shop told me is that when the air springs fail there is no partial failure - the car drops and will not raise up. When the car is turned off and bottomed out, turning it on results in it quickly pumping back up to the expected height but it may or may not stay there.

 

I'm preparing to do this repair myself, and I'm wondering if anyone can tell me the part number for the plastic clip that holds the electrical connectors in place. Since this seems to break alot, I'd like to have a replacement ahead of time.

 

Hi Fellas,

Finally it's time for me to work on the front passenger side air spring. Arnott part is on order and should have it on Friday.

The thread has provided a few good tricks on releasing pressure to get it fit. I can certainly try it, but owning a STAR system gives me one more option to deflate it.

I assume to do it, I need to attach the air line and electric connector on top and go into the menus. I have been there, but my question is:

What is the proper deflated pressure?

The leaked one is at ~5(maybe bar, forgot the unit). Would the system be able to deflate to ~3, and is that low enough to compress the air spring?

Thanks for sharing your experiences and knowledge.

 

Threads like these make me glad I switched to Strutmasters coilovers. It's only been a week, but the ride is great and the error codes are gone. Only drawback is that I can't adjust the suspension or raise/lower it.

 

Ok, we're on message #233 so far, and I'm about to go back and try to read it all, but thanks to this thread, I just ordered Arnott Rear Air Spring part#2113201625 for $405.47 + overnight for my W211, hopefully to get here Friday. My rear left is sitting down and giving the red warning. In addition, sometimes the front left also sits down, and sometimes the rear right sits down. But the worst is the rear left.

DJHudson in post #229, I have exactly same problem you do right now. Like you, I had the air compressor replaced by a mechanic, and that helped. Like you, it sometimes drives straight and sometimes pulls right. Like you, it sometimes sits down too far and sometimes goes closer to the right height. It travels up and down like it's trying but failing. When I'm parked and car off, I hear the front struggling to do something with the air. Is that a sensor or valve? Obviously, you and I have the same problem. I'd like to know what it is, too.

I don't have STAR like Equitiesguy in post #228, but my Mercedes mechanic who does said they checked for air leaks but didn't detect any a few months ago when I went in for this same problem. (When he replaced the compressor, it was enough for it to work right for a while, then it got worse again.)

Here's the other question I have:

On the Arnott order page it says "NOTE: If replacing an OE unit with Arnott Air Spring A-2724 you MUST replace both rear air springs at the same time." I did not order two. I am only going to do one. What happens if I only do one? I've searched everywhere, and all I found is their PDF manual which says: (from arnottinfo dot com slash manuals slash A-2724.pdf):
So, if I do that anyway, will it mess me up? How much is "slight"? The showboat owner before me that put bugeye headlamps, AMG rims on a regular E500 (grrrrrr.... I finally replaced those racing junk with standard sized aftermarket, much better ride, much lower cost, more resilient), etc. also did some aftermarket customization with ride height, causing the front left to be slightly lower than the right and both sides being out of factory spec, and making it impossible to align this car right. I have considered paying the quoted $300 to the local customizer (San Jose: Alum Rock & King), who claims they can adjust the chip, but: (a) most people say this is usually customized by fooling the system with physical measuring stick adjustments, and much less often by chips, so I'm not sure the customizer can de-customize the car back to factory spec since I'm getting conflicting information, and (b) I don't think the car is worth spending $300 on for perfect ride height, as long as in the next 100K miles or so it doesn't cause me too much grief (a year or two -- yeah, I go far). I'd hate to go to the customizer, have him de-customize via the chip a customization originally did with sensor realignment, and then end up with the car (1) too high (ugh) and/or (2) still out of alignment and/or (3) not even, for no good expenditure of money except the customizer's labor, equipment, research and parts.

So, if I just go the path of least resistance, put in only the rear left Arnott strut, then considering ride height on the car is already maladjusted, so then two things would be maladjusted, will it get super wacky? (Or would they slightly cancel each other out?)

By the way:

1. My intermittent leak causes my car to pull to the right pretty hard when it is in its bad position. Sometimes it raises enough to not pull hard right. I intermittently get red "Car too low". Usually when it's red it the ride uncomfortably bumps hard on the bumpy roadway, and I scrape sometimes going across road changes in height. It's getting pretty common that the car will refuse to drive or brake properly, throwing break slippage errors and slowing down the car, and also when it is bad it cuts my braking ability really far down, so I have to get this fixed soon. It also effects my ability to go through curves properly at speed, so I have to go partial speed.
   
2. Could it be a worn out valve? Two months back when I thought I had too much money, not enough brainpower, and not enough time, to do DIY, my mechanic replaced the compressor, and that seemed to help. Now, I feel poor, smart and unbusy, and found out this is relatively easy, so I'm doing this one.
   
3. Today when sitting in the hot sun with the car on to keep the air conditioner on, the car suddenly blew out audibly and vibrations through the cab and sat down INSTANTLY on the left; I've never experienced that before. When I got out to see what happened, the rear left wheel well was very hot from the hot sun, hot air, hot day, hot engine, hot transmission, hot air conditioner, and lack of me moving through the air (just sitting there) all heating it up, which obviously put it over the edge of whatever blew. But what blew? It seems to behave the same now as before the blowout, even though that triggered me to go ahead and order a fresh strut. I see nothing visibly broken. The strut goes up and down, poorly, not properly, but same as for the last few months.

By the way, Arnott has a great YouTube on how to do this replacement (YouTube dot com slash watch?v=Gkml0i61H2A)

 

Yeah, but 2.2x the cost of a single air strut replacement + 4x the number of wheels to do + more complication, and on my junker 275K mile E500 not worth it (I'm only going to put 1 or 2 hundred K miles more so really not a big deal). Plus, with these California roads, I don't know which is harsher: air or spring. (When I test-drove Tesla Model S with air vs spring, the spring was softer, and Tesla used similar air to Mercedes. Too bad I can't afford it now; I failed to get in properly to $TSLA when it went up 200% the last 4 months.)

 

With high res on, you can probably pause the very long set of videos at youtube dot com slash watch?v=Yk1wUXBvlyc and see the torques of many of the items. That YouTube is the same procedure my Mercedes mechanic quoted me to replace the two rear air springs on my car (he is an indie and quoted $2,500): remove rear suspension, drive shaft, exhaust, covers, wheel well covers, heat covers, gas tank hose, break calipers, air lines, and a bunch of other stuff. Why the heck do they remove all that junk when the Arnott only requires a very short version? The Arnott website contained this sentence which probably explains the difference, as also evidenced by the above YouTube sequence of videos (he explains the reservoirs are buried in all that junk):

"NOTE: If you do not want to remove the O.E. reservoir there is a much quicker way to replace the air spring only."

Perhaps if those air reservoirs are leaking, that is a good reason why they have to take down all that junk. That might also explain my bug: if the reservoirs are leaking, then the air control and supply line from the front of the car would actuate the air strut to a limited extent, but then the air reservoir would fail to hold the air, every time. Perhaps I really do need to do the long procedure; perhaps my air struts are just fine and all I need to fix is the air reservoirs and/or their hoses/connectors. What if I shoot tire run-flat or some other in-place sealant into the air reservoirs through their connection ports without taking everything apart? This could turn this fix into a $20 fix if done right, rather than my order of the $405.47+delivery 67.01 ($472.48 complete) Arnott's. Perhaps I'll try that tomorrow.

Edit: AHA! Found someone who did that! He actually fixed his AIR SPRINGS this way:

http colon slash slash forums dot trailvoy dot com slash archive slash index.php slash t-92518 dot html

Edit 2: As I studied about Flex Seal, I finally thought to myself: what if I go ahead with the Arnott air spring replacement (or not), but then get a new/replacement/different reservoir and new hose and just zip-tie it somewhere under there, and abandon the OE reservoirs in place? That would save a bunch of hassle. I wonder if there's a way I could test that.

Edit 3: "The Arnott aftermarket Mercedes rear air spring simplifies installation by eliminating the OE reservoir." -- that's the one I ordered. In what way does it eliminate it? It is obviously simpler -- as I've discovered and discussed -- but they seem not to "eliminate it" -- they seem to instead reconnect it. Let me rewatch their installation video VERY carefully this time and listen to the voiceover (they don't show the reconnection but I thought she mentioned it).

Edit 4: Yes, I found it: youtube dot com slash watch?v=Gkml0i61H2A & t=4m12s
She says in the voiceover "Reconnect the factory rubber hose leading from the air spring to the air spring's reservoir.", but they don't show that. Then, below in the text, they say "but the Arnott replacement is up to 90% faster thanks to Arnott's innovative design which does not use the air reservoir found on the OE version." and "without the OE air reservoir. The Arnott aftermarket Mercedes rear air spring simplifies installation by eliminating the OE reservoir." So, she voiceover'd a reconnection, but the video didn't show it. Also, her sentence means there's a reservoir included (inside) the new air spring, but perhaps she just used bad grammar and was referring to something else. This has become a mystery to me. I'm hoping it DOES eliminate the reservoir, like they said. I'm going to go with that. That, by the way, is an improvement: once you replace the air strut (much easier because don't have to drop rear suspension which is a million steps), the unreachable reservoir and hose leak doesn't matter. In the video, they mentioned putting the hose somewhere where it won't get hot. Perhaps they're talking about permanently stowing it out of the way abandoned.

I hate doing mechanics. I should have done well trading $TSLA and gotten one of theirs with warranty. Stupid stupid me.

Edit 5: right below the sentence I quoted about ride height in my original message above, I found a picture that explains that the reservoir is NOT NECESSARY ANY MORE. See the doc I already referenced (page 1 of arnottinfo dot com slash manuals slash A-2724.pdf). Just like in trading, I never execute the last step -- I get right up to right before and get flustered. Story of my life. My grandfather's too. Just great. Grrrrr

Edit 6: I'm asking questions now talked about in this thread, so I link for you to jump to there:

mbworld.org/forums/w211-amg/467523-diy-w211-rear-springs-bellows-arnott-2.html

Edit 7: I found them for cheaper at http://www.carid.com/arnott/new-repl...pn-a-2724.html according to the above mbworld forum. OOPS!!!! Could have saved $60.82! GRR. BUT they didn't offer next day delivery. With shipping CarID's comes to $362.58. If it ends up I need both, I could get it from there. To order two is $707.23. If I had decided to wait an extra week, I could have saved $127.83 if I decide to get both in the future. I'm not really that upset.

 

the reference to CARID not the same part as A2725 -- its non AMG

 

In order to do away with the air tank reservoir we changed the length of the air spring which provides a really nice ride. You shouldn't replace just one since they will be a different heights. The good news is that instead of 8 hours the dealer would need your indie should only need about 45 min per side.

 

What company is your warranty from? I've tried getting one from endurance but they apparently will not cover my car. I have a CLS55 not an E-class

 

Thanks for this. We pulled the codes the other day (5350, 5356, 5500 - A9/141) and the pressure relief valve came up. The ride and height of the car seem fine, so we'll look at the switch wires in the coming days.

Looking to see if the switch, valve, or both are practical to repair or replace if need be. Does anyone know? Someone said there's a kit out there.

 

Hi MB People. Today we looked at the Airmatic system wiring forward of the front passenger wheel well. Wiring is intact (not chafed). My question is...is the pressure relief valve and switch cited by codes 5350, 5356, and 5500 part of the 'valve distribution block' (as I suspect), or are they all seperate items? I'm moving to replace the valve.

Anyone?

 

HELP!! I can't loosen the lower bolt. It's really seized up, tried everything but heat and impact wrench so far.

 

What a pain in the ***, I got it off, but it was brute force all the way. I am picking up a new bolt from the dealer tomorrow and will finish the install.

 

The pressure relief valve and switch on my E500 are located at the end of the unit itself, not the valve block. There are 3 screws arranged in a triangle. The problems (codes) were caused by worn wiring at the connector which I replaced. Elsewhere in this site a tech explained that the majority of the issues with the pump are caused by electrical wiring failure.

 

Finished the install, I would never have been able to even attempt this if it weren't for this forum. Getting the strut over the lower control arm would have been the hardest part if it weren't for a seized lower bolt. Car is operational again. Thanks for all the help.

 

I am sorry but I do not quiet understand. How do you mean by 'to trim back the tube 3mm from brass nipple'.
Please explain further as you would to a pencil pusher

I apologise, but I really don't know what you mean.

 

snip off as little as possible off the nylon hard hose as the brass fitting deforms the hose as it is tightened. if you do not do this you will most certainly have a small leak that will only get worse. snipping off the end will provide a fresh end for crimping.

 

I just replaced my front air struts this weekend. Thanks for the great write up. Just like everyone said getting the new strut to compress is a real pain. I tried the battery trick which worked on the driver's side but for some reason the passenger side wouldn't compress enough. I took a look at where the air line goes into the strut and noticed there's a small hole. I borrowed my wife's sewing needle and pressed it into where the hole is and air started coming out! It wen't very quick once I got all the air out. You'll still need to use a jack to fully compress the strut but it was so much easier and faster. BTW this was an Arnott front strut.

 

Great thread. My thanks to all contributors, particularly Yacht Master for the extended descriptions and photos.
I am changing the collapsed front left strut on my 2007 E550, have just ordered the Arnott new unit.

I was unable to hear an air leak, but I do have oil running down the inside lower portion of my existing strut.
Hopefully all the great advice here will make for a smooth installation.

 

Latecomer here. Just followed the guide at the beginning of this thread. I found it much simpler to depressurize the strut by applying ground to the center pin of the top connector and +12V to the bottom pin and then to the top pin while pressing down on the strut. remove power and ground with it compressed and it'll stay that way for long enough to get it in the car.

Then, with the car still jacked up and everything connected and back together, turn the car on and press the button to raise the car. Let the car down with the jack slowly in increments of an inch or so and the ride height sensor will open and close the valve to pressurize the shock gradually so the bellows won't be damaged by trying to pressurize it when it's fully compressed.

 

Gonna replace my front driver side next week. Waiting for the parts from Arnott. Do anyone know torque specs for W211 E63 for tightening everything up?