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R Class Rear Suspension Air Bag Replacement

224K views 180 replies 73 participants last post by  injuhneer 
#1 ·
I just replaced both of my rear suspension air bags. My R class has the full Airmatic suspension, which I have already replaced myself the front ones last year at $1000 x 2. I found a company Air Suspension Kits, Air Shocks, Suspension Parts, Struts - Arnott Industries, which sells remanufactured suspension parts. I bought the set of two rear air bags for $299, compared to $550 each ($1100 for both rears) from MB . I installed them yesterday, and so far they are performing like OEM. The air bags are manufactured by Continental, which makes tires, and have a division which is Contitech that makes air bellows and other air suspension related parts. Arnott offers lifetime warranty, as I was hesitant because I thought their would not perform as well or that they would pop when loaded, but so far I am pleased. The replacement is so simple, as it also comes with instructions. The steps for removal are the following:
1.Raise up the vehicle from the body or rear cradle to allow rear tires to drop down.
2.Remove Compressor Fuse located in Engine Compartment (The second large orange 40 amp fuse is the compressor's). Remember to remove key from ingition.
3.Once vehicle raised from rear, removed the rear tires
4. Remove the airline at the top of the air bag on the opposite side from the wheel with an open 10mm wrench and remove the adapter from the line, as the new one already has such piece.
4. Pry the air bag down from the top with a flat screwdriver to release it from the locking pins at the top.
5.Remove the air bag by squeezing it through.
6.Remove and install the white securing pins with a flat screwdriver
7. Install the new air bag with the air inlet towards the inside. Make sure the bottom is seated properly to match the notch.
Reconnect the airline and ensure that it is all the way in and that the colored marks on the airline are against the fitting in the airbag (just push it hard until it cannot go more).
8. Reinstall tires, lower vehicle (the vehicle will drop the wheels into the wheelwells), reinstall the fuse, and turn on the car so that compressor fills the bags (you may hear a couple of pops, but they are normal).
9.Check tha the vehicle does not drop all the way into the wheelwells, as it is a sign that you still have an airleak (leaking air at the connection fitting is the most likely problem), otherwise, you are done!
 
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#32 ·
Thanks for the original post and followups.

I believe I have a similar problem on the wife's 2006 R350 (75k miles), at least the pictures seem the same. The fact that the left rear stays up tells me the compressors are working.

So I took the plunge and got the Arnot air springs in today. As many of the other posters have said, it takes longer to jack and remove the wheel than it does to swap out the spring.

Now only having a little time tonight, I thus far have only replaced the one on the side that was riding low. If there was a problem in an air spring, wouldn't it be on the low side? My problem is that the car seems to be riding the same as before the swap out. The system inflated it enough to raise the car off the wheel, but it doesn't completely level.

Is it possible that a problem exists on the high side rear also? Should I be spending time swapping the second spring, or is this evidence of a sensor or other problem?

Thanks in advance for your help and time!

Dan

P.S. Nice to see plenty of DIY'ers in the MB universe .. I'm used to it with the Saabs and VWs I've had, but good to have it for MB also.
 
#33 ·
I'm experiencing the same issue you have noted above. Although, I did replace both rear bags at the same time although only one was having a problem. I have now checked the air line and fitting and even swapped the ride height sensors to see if the sensor was bad. Still having the same problem of the right rear side sits about 1/2 inch lower than the left. I'm puzzled now as I'm not sure what the problem is. Hopefully, someone here with a little more knowledge will chime in for assistance.
 
#34 ·
My problem seems to have resolved itself. I'm guessing that I wasn't being patient enough, but sometime mid-morning after running an errand around town, we started the car up, and it leveled itself.

So the fix of the OP with the Arnott parts has apparently worked for me, and thus far I have only replaced the air spring on the low side. Too cold and wet to do the other one today, so it's been moved to next weekend.

Curious however, is there a FAQ or Howto on the sensors themselves? Where did you find that information. My cursory searching hasn't yielded much.
 
#37 ·
Want to Thank everyone for their post. This help me out a great deal making the decision to replace the airbags myself.
I did have a couple of issues that I thought I would share just in case somebody has the same.
My right side rear airbag was 100% bad when I started replacing it it was already deflated.
The problem I had with the drivers side one was that it was completely full, at this point I was thinking that this air bag was defective as well because it had no give.
I did not truly understanding the system so I started to cut the air bag open with a knife, luckily no one was hurt from my stupidity when the air bag pop.. what a bang!!
At least I was able to install the 2nd Arnott airbag now so I did.
I put all wheels back on and started the car.
The car leveled out what a great feeling, until I drove it a little and the light came on saying that the car was to low, Happy feeling gone.....
I thought back on what I did and I could not remember when placing the house back into the air bag that it clicked in place like the 2nd one did.
I Took the wheel off and I was right the hose on the right side pooped out, so I pushed it back in.
The problem I then had is that since all the air went into the other airbag that was all the way up again and no way of realising the pressure.
I felt that if I could release the pressure it would level out.
I then talk to a Mercedes mechanic and I was told that they need to put a computer on it to level it out, I paid $118 for them to do that and the car leveled out and was fine.
Happy feeling again..
 
#38 ·
I have a 2007 R350 without Airmatic.My rear right side of the car would drop overnight when the weather was cold.So I read all the mercedes forums and decided to replace the airbag.Very easy to do but the next morning the car dropped again.$300 gone.What I did next was to swap the airlines(left to right and right to left) from the block valve which is located above the compressor below the right headlight.The next morning the left side of the car dropped so I concluded that it was not the airbag.It was the block valve.I bought it from the dealer for $175 and replaced it for 15 minutes.The car has been nice and leveled since then.I lost 300 bucks for the airbags but at least I have spare bags now.I hope this is going to be helpful.
 
#178 ·
I'm curious about how to diagnose air spring vs valve block and this is the only tip I've seen.
But crossing lines seems like asking for trouble.. what were the exact steps? I assume you would do this when both rears are defalted, then inflate both by turning on the engine? then turn off and wait? Are there specific steps to attach the lines at the valve block?

Also, does anyone have the spec on the actual proper ride height for a rear air spring, front coil spring '08 R350? I thinkt he US models are long wheelbase. I don't know how you'd measure it.. maybe ground to the top of the wheel arch?

If someone has a bidirectional scan tool that can adjust or set the level, please let us know which one.

thanks
 
#39 ·
I recently bought a r-350 second hand with 70k on the dash, my wife loves it as well as i do but come next morning the R is leaning on the passenger rear tire almost to the point of the tire rubbing on the inner fender. I manage to buy the a new bag for 150.00, i tell you to replace that bag was as easy as removing the tire. Thank's to the forum that helped me on fixing my wife's car as she is pleased. :) Thank's
 
#40 ·
I have a 06 R350 and the I was getting an error stop vehicle is to low and then this noise would come on and the car would go back up eventually the noise got louder and the car stop raising and stayed low completely....I took it to a mechanic and I was told it was my airmatic pump...I purchased the pump at a dealer and the mechanic installed the pump today for $150. I got in the vehicle and I'm still hearing noise and I can see the car rising. When the car sit for a long time it's completely low and on my dash it says wait briefly as the car goes up...it goes up and the message disappear, I need help because my car has never done either and I'm thinking with the new pump this shouldn't still be happening....Could something else be causing the back to be low?? and if the pump is installed correctly does it still make noise??
 
#41 ·
I have a 2007 R320 with around 70k miles on it. Today the rear suspension sagged and the rear of the car went all the way down, both sides. The message on the console says it is trying to raise the car but it does not succeed. The front is OK.

Would this be an airbag or some other thing like the compressor or the block switch as someone has posted above?

This is going to be a DIY repair so I am looking at the Arnott air bags. I have replaced airbag springs in my Motorhome earlier so I kinda know what I am facing.

By the way, I am pretty sure I don’t have airmatic on it. How do I make sure I have airmatic or not?
 
#42 ·
ok I made sure that I dont have airmatic by the fact that :
1. my car is missing height adjustment switch, right next to the seat heater button [is that really true?]
2. The front suspension struts are simple spring types....no air bag there.

I am looking everywhere in the official STAR service manual for my R320 but I cannot find a mention of a "block switch" anywhere.

I just do not want to order and replace the air springs and later find out that there was something else which needed to be replaced.
 
#44 ·
my troubleshooting steps

Ok so I spent the good part of the day last sunday troubleshooting my air suspension problem and here is what I have found today. I am hoping that someone else troubleshooting this issue does not waste as much time as I did today.

First, I jacked up the car and took off the rear wheels. I sprayed the air suspension/springs with soapy water and turned the car’s ignition on….to the point where the console says “car rising, please wait”.
Nothing happened, no bubbles. Hmmmm…

Then I thought maybe I should look at the air compressor. For that I had to take the front passenger side tire off. I removed the plastic wheel well and found the compressor behind the headlight.

Got my wife to turn on the ignition while I felt the compressor. No vibration, no sound. So I thought the compressor was dead.

I took off the compressor’s power connection and put a meter to the contact….no 12 volts…nothing

I thought that the fuse Well then I traced back the wires to the fuse box on the passenger side of the engine. Using a multimeter I determined that the wiring is all OK. There is a relay which activated the compressor. The relay was also OK.

It was then when I realized that you need to start the engine to get the compressor to run! Yup…..I wasted a couple of hours figuring why the compressor was not working when the display was saying wait, car rising. In reality, it does not do anything! You need to start the engine first.

Anyway, after I started the engine, the compressor started running. However the car would not rise. I removed the thick white air hose from the relay/controller and measured the air pressure using a pressure gauge….it was not going above 15 PSI. The manual says that the air springs operate between 90 to 145 PSI.

Hence I need a new compressor.

I found an OEM one from e-bay at $455 free shipping. Ordered it. Once it comes in I will update this thread.
 
#45 ·
So my fiance wasnt telling me that her car over night was lowering on the drivers side finally I drove the car to Tampa and I guess thats when everything went to crap the "Stop car to low" light came on. I had a few passengers because I was with the kids. Now the car lowers whenever there is passengers. Took the car to an indy and he said the compressors bad but is not sure if the bags are... (I was confused) He said we will have to change the compressor first and test it to see if the airbags are bad. I've heard tons of different things that can make it lower... Leak in the hose, leveling sensor bad, bad airbag... Now I know that the truck has a strut and airbag in the rear according to the pic below... Do I need to just replace the airbag or both.

 
#46 ·
I just finished diagnosing this problem on my R320 ......you can diagnose what is bad by looking at my post above.

Basically it is easy to diagnose the compressor. Just put a gauge to it........it should read well over 100PSI......mine was only 15PSI.
Did your indy mechanic do that or is he just guessing? If he is just guessing it could be an expensive thing to replace just for nothing.

Maybe the airbags are bad instead....and he will end up replacing the compressor only to find out that it was actually the airbag which was bad.

There are only three things in this system:
1. Compressor
2. Valve
3. airbags

Sure there is electronics and height sensors...but they are not usually the problem. #1 and/or #3 is usually the problem.

I'd say first, put a guage on the compressor...make sure it is bad or good...then replace it only if it is bad.

By the way, if the airbags are bad.........make sure you replace both sides........they are around $330 online..Arnott/e-bay.




BTW, if only one side is going down.........I bet the compressor is OK..........that side's airbag is probably bad...........the hoses are made of plastic not rubber..........they probably wont leak. Just spray soapy water to diagnose....easy.......good luck!
 
#47 ·
Thanks rajdude... I'm going to check it out, the car has got to the point where its doesnt even want to lift anymore... So i'm not sure if there is something else to replace, and I hate going to MB or an indy cause FL is so expensive with that stuff. Just for MB to look at my car is $165.00 and for an Indy to look at my car $95.00 and all their doing is looking at it. Not that I mind paying something if its worth it... But I feel its a rip off
 
#48 ·
Hey I am all for Indys....in fact I never go to the dealer.

However, I usually end up doing all the repair work myself (sometimes I have taken it to the indy for diagnosis.....and once when it was the middle of winter and I could not handle the long repair outside {I don’t have a garage]

Anyway, I just repaired mine....more on that on a later post.

My car also was at the point that it would not lift anymore. However the difference between mine and yours is that yours sagged from one side first [that points out that an airbag was probably bad]. Mine...both sides went down at the same time.

I'd say check the compressor first...it is super easy! Just take off the right wheel, then the fender cover inside it...and boom...you see the compressor right behind the headlight.

Then start the engine and see if the compressor even runs [the car should say it is rising first for the compressor to turn on]. If it does not, maybe the relay got burnt out OR the compressor is bad.

Relay = cheap and easy fix
Compressor = $450 and still an easy fix...half an hour job tops.

If it runs....take a 12mm spanner and remove the white plastic hose, the thick one from the valve thingy. See how much pressure are you getting [while the compressor is running]. I had a pressure gauge from Harbor Frieght….30 bucks or something.

Maybe you could even put a finger to it and it should be able to generate a LOT of pressure….mine was pfftttt and no pressure.

So that is how you can check your compressor.

Good luck.
 
#49 ·
my update

Ok here is an update on my repair.

The compressor I bought from e-bay $455 fre shipping works 100% fine. It is made by the same company AMK which made the OEM compressor...looks identical too. Arnott sells it for $470 + shipping. Mine came in a box which said Arnott on the outside. Probably was drop shipped from Arnott themselves :confused:

But tell you what....easiest repair I did on this R320, I swear!

Diagnosis took me hours and the compressor replacement took me less than an hour….actually the replacement took just 15 minutes or so. Just three nuts and the compressor drops down. Two hoses come off easy. Most of the time was taken in re-installing the fender liner and the wheel.

After I installed it, the moment I started the ignition, the compressor started running. Within seconds the rear of the car started rising…and it has been good for the past 2-3 days.

I did spray soapy solution and checked for leaks before putting everything back together.

hope this helps someone. :D
 
#51 ·
I was quoted 4500 usd for replacing left front.
This is including work and parts, here in Norway (Oslo)

I got a quote from Arnott
A-2587
$344.80 + $84.23 Shipping (2-3 days)

But this is only the "bag", will it be harder to change this, than the whole strutt ?
 
#53 ·
Yes, NOK 24900.-, and according to the service manager is most of the cost parts, and hardly any labor!!

Anyway, if anyone have done the "bag only", I would be grateful if you could comment on hove difficult this would be.
According the Indie, there is a need to have some software to read out some level info prior to changing it, and re align after swap?
 
#56 ·
Can you reset the air leveling rear?

My 2006 R350 just developed the right side lean and it only has the rear air springs not the full Airmatic. It appears as if the left side is maximally inflated though. is there a way to reset the system to level back out and let air our of the left side. Or do I just need to take in to a repair shop and have them run a diagnostic. Seemed to have occured when the weather got colder this week.
 
#57 ·
must change relay

For what is it worth...after I replaced the air compressor.....at the very first engine start in the morning......the console gives an error......"Malfunction" with a upwards arrow sign inside the R class shape.

I read that it is mandatory to replace the relay while replacing the air-compressor. So I bought one from the local dealer and replaced it today. The part number is A002 542 7619. Around $29.

Unfortunately the error message is still there.

Strangely:
1. The car's suspension works fine.
2. The error message comes only once....in the morning....it never appears again for the rest of the day.
It is almost seems like it is dependent on cold temperatures. Once the car warms up the error goes away.
 
#59 ·
There is no built in gauge. You have to buy one. I got one from Harbor freight...it came with the right adapters. I disconnected the white hose/pipe coming from the compressor to the "distribution block" ...and attached the gauge. Start the engine and read off the pressure. It should be over 150 PSI.
 
#60 ·
Thanks Rajude, picking it up today... Changed the airbags and the car is fine, but still want to check out the compressor. Now I heard from a single person that I will have to bring it to an indie to have the car leveled, because I changed the airbags. How true is that? I thought the r350 came with an auto leveling system. Correct me if I'm wrong
 
#61 ·
If the car is rising after replacing the airbags I think your compressor is OK.

IMHO there is no need to get the car leveled...unless you messed up the leveling sensors...I believe they are around the airbags somewhere.

Level is controlled via the sensors and the air distribution block in the engine bay. Yes the R class has a auto leveling system...but I thought it was only front to back level...not side to side...but I think I am wrong there.......otherwise why would it have two level sensors and that distribution block / solenoid.

By the way...after the compressor replacement....are you getting any "malfunction" message on the car's dash?

Lastly make sure you change the relay...it is needed to satisfy the air compressor's warranty. (see my post above about it)
 
#62 ·
Dammit,

I just saw this post after I paid MB $766 for a new rear airbag!! :banghead:
 
#63 ·
Well FYI to everyone else...

I changed the airbag and "Wa-la"! Problem fixed and I found a rubber hose that cost $6 to replace that connects to the compressor busted. Thanks Rajude if it wasn't for u I wouldn't have looked... I went to my Indy and one of the techs (looks like a new guy) advised me if I didn't touch anything else (ie. arms, joints) and just removed the bag and nothing else I don't need to have it leveled. Everything is cool. Once again thanks guys!
 
#64 ·
Problems replacing front air bag...

I'm having problems replacing the front driver-side air bag. I can't see where the airline connects at the top or how to remove the 3 nuts on top of the shock. Seems like I'd have to remove a lot of stuff to get to it. Has anyone done this before? Any help would be much appreciated!
 
#66 · (Edited)
I'm having problems replacing the front driver-side air bag. I can't see where the airline connects at the top or how to remove the 3 nuts on top of the shock. Seems like I'd have to remove a lot of stuff to get to it. Has anyone done this before? Any help would be much appreciated!


I know this is the "rear" airbag thread but when the car has airbags all the way around then it is all inclusive I guess. :)
I did my front pass side bag on my 08 R class so I can tell you some of what I saw.
After removing the cowling above the engine, then the brackets that bolt to it at the ends, the bracket for the strut top can be accessed. The outter bracket will have two small bolts that seem to be at the fender outter seam but will let that outter bracket come off.
Two of the nuts are readily visible when the strut mounting bracket is exposed but the third nut is down inside the bracket and out of sight till you go looking for it. The air line runs through a rubber grommet in the back side of the strut mount bracket and it is a tight reach to loosen the line down through the bracket prior to removal. It might be possible to lift the bracket and loosen the line fitting from underneath it better.
If you get a bag from Arnott Industries, like I did, the instructions are pretty good for getting through the installation.
*************** DONT start the engine while the car is raised!!!!!!!!!!!!!!
I did and now my sensors are out of whack. The instructions state this warning but My daughters wanted to watch a movie so I started the car for them before I read the warning in the instructions.......now the pass side is higher than the driver side and I have to get the sensors reset. :mad:

The bolts on the sway bar link and lower arm strut mount are very tight. You will need some serious breaker bar power to get them loose.

Good luck and keep us posted.
 
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