Reservoir looks fine couldn't find any leaks there. But why the rear doesn't want to raise I don't understand. Now the front of the car is really high and rear is down on the ground.

 

Faulty rear height sensor?

 

It shows -69mm when i move the car it moves around -68 and -70 so I think it is working properly

 

Disclaimer: never worked on MB airmatics; however, did some bus air suspension in my youth.

can you measure pressure at the different junction points? Say after the splitter in the rear? At the entry point of the airstrut?

You got pressure so you are good. From there it is just about continuing measuring until you get to the unit. Pressure at the entry of the unit, it does not mean it will raise since the entry valve can be stuck closed, so no air in. Say the module at the top is not working, so no inflation

My 2c

 

Hey, I was using Autocom this time it only sees the pressure at the valve block I believe it doesn't show whats the pressure at each strut maybe I would be able to see it with MB Star, but I don't have one at the moment. So I'm working with what i got. But my Rear Right strut was working well when I have deflated my car fully I can't raise the rear of the car but I was able to raise the front which is weird.

 

You may need to find the wiring diagram. If I understand correctly there is three pin connector at the top of the unit: ground, inflate, deflate. If the inflate is not active, the unit will not inflate regardless of entry pressure.

Find a way to measure pressure as close as possible to the unit, physically or electronically, and verify there is voltage at the connector to allow the valve to open. Basically, there are 3 possible point of failure at the entry: voltage, pressure, valve hardware. If the first two pass, i.e you got correct voltage and pressure, the problem is downstream; otherwise, trace the failing one backwards

Is it possible to introduce some kind of T junction for a pressure gauge?

Detach the electrical connector from the top of unit, and measure the voltage on both actuator pins, you want inflate

No other ideas, sorry.

 

I could Check if there is pressure at the rear struts by disconnecting air hose that goes into the strut. And yeah I have heard something about using 9v battery to deflate/inflate struts seperately. But I really don't think that there's same issue with both struts. Also I think that i'd get another fault code if there were any more problems with wiring.

 

Is it possible that there are some problems in the Control module or that it is not working properly?

 

Anything is possible but you need to establish a reference point when troubleshooting a system, and systematically move upstream/ downstream based on factual information w/o jumping steps. Otherwise, it becomes a frustrating guesstimate game.

IF, big if, the system has a failsafe mechanism, i.e. shutdown whenever detects a problem you need to find/catch the problem before the failsafe is triggered, say 10s?

Airmatics videos for the W211

 

Yeah I have seen the video I have changed compressor aswell, even though when I erase the fault codes it doesn't want to raise rear. Here is what I have done already: Changed compressor, Valve block, checked all pressure lines connectors sprayed with soapy water, rear axle distributor, central reservoir and both additional volume reservoirs aswell, checked all connections to the compressor and valve block. I haven't checked the fuse on the passenger side becouse compressor is working so that shouldn't be a problem. Also when i took my car to the dealers they said that the airbag was good.

 

Be careful, you can change every single component and still end up with a problem, same or different.

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If the assumption is the airbag is good, whatever that means, you must verify that there is the correct pressure at the entry point, not elsewhere, and valve is activated for inflation, voltage. If you do not have the computer diagnostic, you may have to do the old ways: measuring with gauges, voltmeters, and tedious tracing the flow of information: neumatic and electric.

For example, the pressure at the pump is 15bar, the line is clogged downstream, there will be no leaks, no raise. You need to check at the important points and troubleshoots where the data leads you

 

Update: So... Since the air lines on my valve block are not marked by any colours I have always connected them like they were when I have reciever the car so I have tried to play around and switch them with each other. Compressor air line was put into the Rear axle distrubutor's position Central reservoir airline was put into the compressor's position
Rear distributor airline was in Central reservoir's position.
After I connected everything like it should I finally have pressure in the airlines and I have found a minor leak in rear distributor.

 

Glad to hear you are out of the woods.

That means someone was messing around the valve block before . Not a bad idea to tag those lines with some colors. Hope you did not spend too much in parts that may have not been needed.

Once you fix the minor leak, give it a nice wash, polish and enjoy a nice ride

 

 

Thanks a lot. I really hope that problem is in the rear distributor but also if the problem was in the rear distributor both rear struts would drop in time not only left one. I have tried to unscrew the line and I just pulled it out it was glued in and distributor had no thread at all.

And about the parts well...At least now I know they wont break any time soon, or at least shouldn't break.

 

I hope you understand that is someone glue it when it shouldn't, and pressurized the system before the glue dried completely, your line downstream may be compromised, i.e. clogged. Even worse that glue may have found its way into the entry of the unit. That is why there is a filter up front of the car .

It seems you need a new rear distribution box, and diagnose the line is CLEAN downstream. I would disconnect from the air strut and check air flows properly, again measure pressures.

Here another thread https://www.benzworld.org/threads/wh...-part.3063354/

 

For now my car raised itself I'll keep my eyes on heigh levels and pressure in the system to see if it drops or changes. For now I'm not getting any Malfunctions I'll check in with the car in 12 hours and I'll see how it goes.

About the glue it looks like it was dry I althogh I saw some glue leftovers in rear distributor itself. I have bought a new one and changed it. Thanks for the info

 

Someone who worked on this car before me it looks like he did not know what was he doing or he did not really care... Thats why I was surprised about my problem becouse I have never seen something like this in any forums. And I do wonder why Mercedes made plastic threads everywhere for example rear air distributor, compressor and struts.

 

Have you looked at radiator overflow reservoir?, And its hose? There is plastic everywhere near critical components

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I'll deffinetly have a look. If previous car owner worked on this car like he did on Airmatic I'll deffinetly have to look at all of the components of the car and make sure that there are no more problems like this. I hope I wont find any more glue where I shouldn't find any​​​​​

 

Would you mind sharing how many miles on the car? Do not recall reading if the car is the V6 / V8, M272/M273

 

It is actually a V6 OM642 it's a 3L diesel engine. And it has roughly 200.000 miles on it.

 

Update: I came back to the garage rear left side looks lower than the right side. Rear axle height dropped by 17mm I'm not sure if the right side dropped becouse of extra load from the left side or is it leaking too But I get no malfunctions this time on instrument cluster.

 

From what I understood so far about the MB Airmatic is that it keeps the car leveled sideways, i.e. if one side drops the other side matches it.

That is good news, but the next steps may be w/o the computer help.

It seems the left side is the main problem. I understand the air-strut's valve can keep the air within the strut even if disconnected once filled. I think the next step is to find the air leak on the strut itself, i.e. soapy water test?

I have not done a soapy water test in 30 years, but I think it is a lot easier these days:
1 - You need another set of eyes, and good memory --> record it using your phone or else. This allows you to go over the video in case you did not see anything obvious.
2 - Also, eyes are not that great to capture at a distance in closed quarters, poor lighting; however, hearing it is a wonderful thing --> use a microphone attached to a stick and move it (record as well) around the strut. Air leaks are usually at the top near the entry point, or from the bottom where the bag hugs around the cylinder. If dirt comes into the lower half and gets trapped between the bag and the cylinder, the strut will start leaking at some point (at least that used to happens 30+ years ago)
3 - If you are still wondering if the right unit is correct, you can disconnect the electric connector at the top once at the right height so the computer does not deflate it in an attempt to level the car. That will isolate the real (and hopefully only) culprit.

You really need to fix the leak, or it will wear the compressor out at some point and you will be back to square 1.

 

Seems you've come full circle on this.