MB E500 2004 66k miles rear airsuspension losing pressure when raining
I have a MB E500 2004 66k miles. When i went to work one morning two 3 weeks ago i found the rear part of the car lowered. After i start the car and press the button any of the modes it will go back up and work fine. It will stay fine for days. The problem occurred again today after a strong rain yesterday and during the night. It was harder to level the car but it worked fine. The car stay leveled few weeks after that happens. Today i have noticed that the left rear side of the car was completely down and the right side was a bit higher.
WHAT might be my issue ? Is this water in the air system or changing of pressure because of the sudden change of the temperatures and the rain ? The car has been driven very carefully and has only 66k miles so i doubt it would be suspension issue ? What are your thoughts ?
Last edited by smartstyle; Mar 14, 2016 at 01:48 PM.




Unfortunately with computer control and complexity of the system - troubleshooting with crystal ball has low success ratio.
I rebuild compressor on my 2004 model and noticed dryer soaked with water in very dry CA summer.
When your original (?) air bags might be pretty aged, servicing air compressor is cheap and recommended regardless.
Of course, Kajtek1's advice is solid. Check codes, troubleshoot and make sure to identify and compartmentalize the actual problem.
If you find you need a replacement, then you have to decide what to do. You could go with OEM new bags, rebuilt bags, or aftermarket.
Depending on your model and part needed, Arnotts should be about $600 - 800 for a set of 2 (http://www.ebay.com/itm/Rear-Air-Spr...xW1pLn&vxp=mtr). Labor depends on where you are and who you know. I didn't pay more than $150 or so total, but that's probably lower than most will find. The guy who did mine also did it in a parking lot underneath an unblocked jack in 130 deg F weather, and that's probably hotter than you will find. He managed to do it without dropping rear suspension, despite having never worked with aftermarket replacement parts before. Anyhow, the result has been great for me.
Unfortunately with computer control and complexity of the system - troubleshooting with crystal ball has low success ratio.
I rebuild compressor on my 2004 model and noticed dryer soaked with water in very dry CA summer.
When your original (?) air bags might be pretty aged, servicing air compressor is cheap and recommended regardless.
I also understand the relay can be problematic. It seems like a cheap fix...




What a message "compressor allowable working time exceeded" will tell you?
Soapy water is good if you have a way to pump pressure in the system.
Not having SD I installed a T on the air line and put pressure gauge on it
That allow me to troubleshot what I think were 2 problems.
One was compressor wear with drier soak in water, the other turn to be pinhole in the tubing right above the rear axle.
I have rear only air, so single T allow me good troubleshooting.
Once I cap the bags line and tested the compressor after rebuild making close to 200 psi and holding after.
Than I reversed the connections and hooked up garage compressor to the bags tubings.
It become fast evident that I have a leak there.
So soapy water, car on ramps and head on to look for the problem.
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I installed it behind inner front fender as this was close to compressor.
But even the pressure gauge allows me to monitor the system, I had to pull the wheel and inner fender for full troubleshooting.
Later on I discover that rear tubing goes under rear seat - what would be much easier accessible location.
Hopefully not something I will have to worry for at least 5 years, but somebody might want to follow my idea.
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I installed it behind inner front fender as this was close to compressor.
But even the pressure gauge allows me to monitor the system, I had to pull the wheel and inner fender for full troubleshooting.
Later on I discover that rear tubing goes under rear seat - what would be much easier accessible location.
Hopefully not something I will have to worry for at least 5 years, but somebody might want to follow my idea.
I work for a MB dealer and had them replaced in our shop. I installed the Arnott air springs, not the factory MB air springs.
Two benefits of the Arnott springs, 1 they are about $120 less each than the MB part and you can replace the springs without dropping the sub-frame, which you would need to do with the MB parts (due to an additional canister).
We installed the new springs and left the old canisters in there and just cut the hose that connected it to the old air spring.
It may not be necessary to replace your springs, but I would highly recommend replacing them as your air leak is putting more strain on the compressor. If your compressor goes, you are going to wish you had just replaced your springs!
Just my advice/opinion, but let me know if you have any other questions
I work for a MB dealer and had them replaced in our shop. I installed the Arnott air springs, not the factory MB air springs.
Two benefits of the Arnott springs, 1 they are about $120 less each than the MB part and you can replace the springs without dropping the sub-frame, which you would need to do with the MB parts (due to an additional canister).
We installed the new springs and left the old canisters in there and just cut the hose that connected it to the old air spring.
It may not be necessary to replace your springs, but I would highly recommend replacing them as your air leak is putting more strain on the compressor. If your compressor goes, you are going to wish you had just replaced your springs!
Just my advice/opinion, but let me know if you have any other questions




My system holds 120 psi in the morning, so if yours does too, that means the problems is in the bag.
If you see the pressure dropping in the tubings, the leak is on the line, or compressor check valves.
Obviously with complicity of the system you can have several small leaks that will take some time to rule out.
Last edited by kajtek1; Jun 3, 2016 at 06:37 PM.


