guess313

2009 - R350

Rear passenger side air spring was low and I have replaced it with Arnott but it stays almost same low level

I replaced the rear driver side air spring as well - Now passenger side is up and driver side is low.

Can anybody please help ?

starbound01

From what you wrote... either the sensor(s) or the distribution block.


But I will add, did you soap test your air connection at the new bag? Maybe its leaking or not installed correctly. Is it bottomed out? Does it try to raise up (compressor runs) and falls or does it just sit at the same location.


The HIGH side is likely just over inflated. The sensor should pull it down to normal level but there are many threads where 1 side is high. I don't know how many sensors there are on your R350. If there is only 1 then the lob sided stance is over inflation. You could bleed air at the distribution block to lower it and see if it pumps back up.


Another thing you can do to test the height sensor is jack the vehicle up so the wheels extend down (vehicle running) this will tell the system the vehicle is too high and should let out air. You could also check the height sensor to see if it's frozen (corrosion). Just don't loose the anchor point or you will have to get MB to adjust it.


I'd lean towards the distribution block since the one side is way high, but I am not looking at it.

guess313

Soap test didn't show any signs on old airbag but I didn't check after installing new airbags


It doesn't stay same all the time.
Compressor works after starting the car and both side go high but one side stays low. I mean, lower side (rear driver side) move up but still stays low comparing to other side because passenger side also go up. It is about a 2 inch difference which stays same all the time. After I park a car, next day both side go down little bit but difference stays same.


How can I bleed the air ?

starbound01

Your vehicle height should not change overnight with new airsprings. If you are starting the vehicle and height goes up, its because the height sensor is calling for air at 1 or the other corners. Since you are saying that one sid is low and the other is going up AND you are lowwring overnightr AND the same problem remains after replacement. I suspect your valve block needs to be replace or a tube is leaking. That is where the air bleeds out.

I doubt the new bags leak, but soap test the tube to airspring connection to make sure it is not leaking. The airsping soap test is a waste of time IMHO - especially since they are new. If the joint is good, check it at the distribution block. Also, there have been reported issues with tubing cracking.

The distribution block is not hard to replace but its somewhere in the $300-400 bracket

guess313

Thanks Starbound01 for detailed replies and all the possibilities you thought could be the issue.

Issue has been resolved now - It needed calibration.

So, for all those who are having a height problem and your car doesn't adjust automatically after replacing airbags and after driving few days. Go to dealer or the person who has Mercedes system to calibrate and adjust the height of your car. You could even adjust the height of airbags according to your choice but I would suggest to leave it on the height where the car and it's chassis are parallel to ground.

Mercedes technician told me that it is normal when you car lowers down little bit overnight and when you start the car; and air compressor runs and adjust the vehicle height.

guess313

Issue has not been resolved and the car went back to same condition.
I have checked sensors and they seems to be okay physically and no error code showed in Start diagnostic system.
Air compressor runs and lifting the car, so, it looks fine.
I have ordered a valve block and going to replace it.
Can anybody tells me how to access valve block ?
I have read for compressor, you have to remove the wheel, is it same for valve block or can I access it from the top ?

starbound01

Valve block is behind the passenger side headlight

guess313

I have replaced the valve block and compressor relay but issue is still same. Compressor is running more frequently now and it seems like there must be a leak somewhere.
I don't know what to do now. airbags, valve block have been replaced. Air compressor runs fine because it make a car higher after start. Height sensor looks fine and there is no damage there. I think I have to examine the whole airline now but it will be very hard to do. Lets see

When I removed the airline from valve block, I noticed that there was a more air pressure on one side and it took a while to release. Both airbags were empty and compressor filled the air. It was almost same height in the beginning but the difference start increasing and now it is about 4 inches

guess313

Once again, it seems like problem has been resolved. The issue was with airline which was not completely inserted in to the airbag. It was the same gap on other side but that side was not leaking. There is a color ring mark on the airline which should be close to the airbag nut. Actually I didn't go underneath the car to insert airline and just inserted it sitting outside and there was no visibility to confirm if it inserted properly. Once you pull it to check if it is locked, the lock inside the nut lock the air line at that place; doesn't matter if it is inserted all the way in or not.

I am thinking to sell my valve block on ebay now, the one I have changed butit was not an issue

Thanks starbound01 for help