a930rocket

The entire right side of our 2006 R350 is sagging (3") compared to the left side (or maybe the left side is high?). The car does not have air shocks and a search here has come up empty.

Any ideas on what to look for?

Edit: The dash says to check the tires and reset the Run Flat Indicator. All tires are good.

a930rocket

After asking and looking around, it appears it might be the air spring in back.

Thoughts on where to buy and how hard is it to replace them.

Thanks!

rosswell

Hi. My 2006 has just begun this as well. The rear struts are air supported in all models so that the car auto-levels itself when weighted/loaded in the rear. (Ever noticed how when unloading 4 or 5 passengers when parking, the car stays higher in the rear once empty - until you re-start it and it levels out again?) One of my struts was replaced under warranty earlier, but the other one has now failed and my car occasionally is very low on the one side as the air bleeds out (only intermittently - about once a week). I'm going in to have it fixed soon. (Car pumps itself back up when started but this needs to be fixed).

a930rocket

I was looking at the air springs tonight. The right one is flat as a pancake, while the left one is inflated and hard as a rock.

Anyone have a link to replace it, etc. and any other parts that might be wrong with it.

I thought about spraying soapy water on it to see where the leak is from as a start.

vorozhbyt

Hi a930rocket,

Pls go to arnottindustries.com this is the best value for money, IMHO. And yes, probably you'd like to make sure that air spring is at fault...

Good luck

a930rocket

I've soaked the right rear air spring with soapy water while the engine ran for 15 minutes and either didn't get the right spot or the air line is leaking before the air spring. I heard no hissing or air leaks at the air spring.

I could see the air line run into the sheetmetal above, but where does it go and where is the air spring compressor? I want to trace the lines from the compressor to the air springs

a930rocket

Had a thought last night. I need to support the control arm and possibly move the sensor to activate the air pump or valve to send air to the air spring.

Thoughts?

a930rocket

Pulled the air line off the bag, started the car and no air. Manually adjusted the ride height sensor and air came out the hose. Filled the air spring off my shop compressor and the bag filled up and held air.

Reconnected the air line to the spring and while adjusting the sensor, the spring filled ip and held air.

Ordered a ride height sensor, so I'll pop that on and see what happens.

user 823908234

a930rocket, Thank you!
Seriously, thank you for posting all your findings day after day. Sometimes we read and gain from others' posts, and think that somehow the poster knows it. Well, I'm reading your post like a shop manual, because some day my 07 is probably gonna do the same thing. And well-written, too. Thanks again!

a930rocket

Your're welcome!

Fortunately, my learning experience on the car has been short because our car has been pain free (knock in wood) except the leaves in the air box intake and that was minor except for Baker MB's lousy attitude towards warranty.

With 110K, I'm leery of keeping it much longer.

If I could talk my wife into a Jetta TDI, I'd be all over it.

a930rocket

Well, I'm a little stumped.

Before replacing the ride height sensor last night, the right side air spring still held the air I filled it up from several days ago. It appears to work, but the car is still low on the right side after working on it.

Went out this AM and the right air spring was flat/no air.

Turned the car on and it pumped up, but not as high as the left side.

A few questions:
1- What causes them to bleed down? Leaks I know, but it held air for several days. Is there a check valve?
2- What is the height of the rear fender lip after starting and no load in back?

Maybe I need to bleed the left side and have it fill both at the same time.

Thoughts?

hcetzneb

Most common thing on the r classes is the bags.. between 80-100k they start to go.. but also it can be the switching valve which isnt as common as the bags but a close second...

dont think your sensor is bad... when you manually moved the sensor and the air started to come out it proved it is working..

Its easy to see leaks from the valve but the bag is hard they leak at the rubber/plastic joint and also the fold marks can leak

a930rocket

hcetzneb - Great info. Thanks.

Where can I find the switching valve? How would I test it? I'd like to narrow it down before I spend more money.

I was going to swap right and left sensors tonight to see if that made a difference.

a930rocket

Pumped up the air spring and did another soapy water test. Looks like the right rear air spring is leaking.

I'll order a set from Arnott, but anybody know where the switching valve is loacated?

Also, is there a "Promo Code" for Arnott?

hcetzneb

The switching valve is above the pump in the right front wheel well.. but to see if its leaking you can see it when you have the hood open behind the pass side headlight it will have 3 air lines.. and a connector .... you can soap it up but sometimes the leaks are internal

a930rocket

I'll take a look tomorrow, but don't plan on getting too involved until the new air springs get here.

a930rocket

I replaced the air springs tonight and it leveled out right away. I'll check in the morning, but this should fix it. Should have bought the air springs to begin with I guess....

user 823908234

a930rocket, again, thanks for your posts. Good information here. I guess you did use Arnott- they make Harley shocks, too - always good reports. Congratulations. Wish I could have contributed. As we approach 80k miles, I have a much better understanding of what to look for.
Now if only I could squeeze under the car . . . ooof ...
Enjoy your ride!

a930rocket

Yes, I did use the Arnott air springs. Great service.

The only time to get under the car is to swap out the air lines. Other than that, it's all from the side.

BTW, I used two floor jacks where the rear control arm mounts to the subframe to raise up the back end and then used jack stands to support the car. Plenty of room to work.

a930rocket

Thanks Doug. Already ordered and installed them before your post.

Great product!

rverrier

My car is also in the same situation and needs the bags replaced. Arnott is currently on backorder for a couple of weeks. Is it ok to drive like this for short trips. Couple of miles to the train????

a930rocket

^^^^ I would say no.

My local MB Indy said not to drive it with a bad spring. Might cause more damage.

MBTec

My wife's 2006 R350 just developed the same problem on the right rear. a930rocket, is yours 4matic? I am thinking about trying this, but want to make sure I'll be able to see it through without too much complication or specials tools needed.

Thanks in advance for any input.

mbph

Great write up. How's your car holding up? Did these replacements solve your problem? I have the same problem with my 03 E55.it sags on the rear every 3 days if I don't use it.

wescx005

Morning, been reading alot and had a question. First what I have and what I did....

I have a 2009 R350 and the car sags / lists to the left (passenger side). I ordered ad replaced the airbag and when the car starts the car goes up half way then the compressor kicks off. It doesn't loose air, the next morning the bag is still where its at ad the bag is hard, just not as hard as the drivers side. When you thump the bag its harder and makes a different sound. So sounds like the sensor or module is telling the compressor to kick off.

Question I have is mentioned above there is a manual adjustment for ride height sensor ? Where is this located at?

Thanks in advance...