S212 rear suspension puzzle

[StuRox]

My 2011 S212 seems to have a fault with the air suspension, which I know is common, however mine sometimes sinks and sometimes doesn't, and on one side then the other.

Indi garage said best to replace it all, which is a huge bill, anything I can look for first?

 

[zipdip]

Well your car being a estate ,does it have the air suspension only on the rear,if the car is running at the right height it is unlikely to be the level sensor or arm,there are only two main reasons for the suspension to lower and that is a leak on the pipework or the airbags themselves,your indy has said change both airbags,did he check for a leak,I have heard that there is one bit of pipe work at the rear that can have a minute split in it,I do not know which bit I have never owned a estate but this air suspension problem is a popular topic on here and just maybe somebody who has had the same problem will be able to tell you just what has happened.

 

[StuRox]

Yes, just air at the rear.

Whe I left it at the ndi it only dropped a couple of mil in 4 days, yet on my drive after 2 days it's on its bump stops, so oy difference is my drive is not level and one side is lower, but told the garage that but as he saw no drop that was beyond the norm he couldn't do anything

 

[Londonscottish]

Yes, just air at the rear.

Whe I left it at the ndi it only dropped a couple of mil in 4 days, yet on my drive after 2 days it's on its bump stops, so oy difference is my drive is not level and one side is lower, but told the garage that but as he saw no drop that was beyond the norm he couldn't do anything

I've got full Airmatic on mine with a slight leak at the near side rear. It was more noticeable over winter but in the current weather the drop is extemely slow.

My indy soap tested all the pipework he could access but couldn't find a leak. As the next step is dismantling things he recommended getting new air springs as in his experience that's where the problem lies in the vast majority of cases.

Arnott replacements are now below £300 a side on eBay so it's not a big a hit as it once was. It's not a huge job so the labour shouldn't be too bad.

Before I get it done I will ask if there's any chance the leak is in some hidden pipework. Wouldn't want to change the bags and find that the leak was somewhere else.

 

[StuRox]

Amd then to totally confuse matters it can go a week without dropping.... No logic

 

[StuRox]

His advice was that if I drive it daily, leave it alone as its pumping up fine....

 

[BlackC55]

The advice you got is spot on. You have a leak that's for sure. To determine where is the hard bit. The suspension does behave just as you have described. We have been here many many times. We have replaced just one bellow, then a few weeks later the other leaks. Replaced just the bellow and then the pipes leak... The bets thing to do to stop it happening completely is to replace both bellows and the pipes. Every car we have done that to has been perfect ever since.

 

[StuRox]

Yes, that is what the Indi said, pretty much word for word, esp so he then doesn't get it back with another leak. It's just the £2k bill I can't take at present, esp as car is 10 year old and only worth around £8k, such a shame really

 

[steveq]

I suggest that you check the pipes for leaks.
If you don't find any leaks, I would then just replace the air suspension units.
I don't know the cost of MB units but it is possible to buy non-MB units for about £350 for a pair. Fitting them can be a DIY job.
That is what I did about 3.5 years ago and it has been fine ever since.

I understand that the professionals have to recommend the full replacement job but the cost makes it uneconomic.

 

[zipdip]

Arnott are the best to use if not going MB,there are others out there but you take a chance on quality

 

[steveq]

I just looked at the Arnott site just now and they don't seem to have any units for the S212 at all.

When I was looking 3 years ago, Arnotts had units but would not sell the units directly to me.
I found 2 other suppliers who would and selected Aerosus based on availability and price.
Their units arrived quickly and had a 2 year warranty.
They solved the problem and have been perfect ever since.

 

[Londonscottish]

The advice you got is spot on. You have a leak that's for sure. To determine where is the hard bit. The suspension does behave just as you have described. We have been here many many times. We have replaced just one bellow, then a few weeks later the other leaks. Replaced just the bellow and then the pipes leak... The bets thing to do to stop it happening completely is to replace both bellows and the pipes. Every car we have done that to has been perfect ever since.

When you say "replace the pipes" which ones are you referring to?

The whole lot or just the ones you can only access when you're doing the bellows?

(I'm pretty sure my indy said that there were some hard to access pipes that could only be reached when dismantling starts?)

 

[StuRox]

It's just a bit of a nightmare that may result in the car going....

 

[BlackC55]

When you say "replace the pipes" which ones are you referring to?

The whole lot or just the ones you can only access when you're doing the bellows?

(I'm pretty sure my indy said that there were some hard to access pipes that could only be reached when dismantling starts?)

The pipes from the valve block to the bellows. They are easy to access when the bellows are out.

 

[Londonscottish]

The pipes from the valve block to the bellows. They are easy to access when the bellows are out.

Is there much additional cost to doing them at the same time in terms of parts and labour?

 

[Fady]

Have the same issue on my car. 2010 E350 CDI Estate which I have owned since 2012 and now on about 66k miles. Just pre-lockdown, so early March, I noted that it was leaning on one side. I took it in to my indi who had the car for 3 days but reported that there was no drop. Said that performed star diagnostic check and cleared a stored fault with the suspension control module.

I brought car home and all fine until about a month ago when I noticed that now the opposite side had dropped (does seem weather-dependent as seems to occur on cold mornings) . So I invested in the iCarsoft MB v2.0 diagnostic tool (finally) to this time check for error codes myself. Before it arrived I had cause to shuffle the car across the drive when suspension obviously re-adjusted to correct height. The thing is it has now remained like that since - so no drop in a further month and I've only taken it out on the road twice.

Not really sure where to go with it. I had been looking to replace it having been keeping any eye out for an S213 E53 of the desired spec for a good few months. With the way of the world, that does not currently seem to be a sensible thing to put money into in my eyes. At the same time I would be loathed to spend money on it unless I was absolutely sure that there is an issue that can only be resolved with new components.

 

[Arkangel187]

I have more or less the same issue on my 2010 S212 E250.

My problems started when the rear passenger top mount broke, taking the level sensor arm with it. This caused the car to go extremely and comically high at the rear. I had it towed to a local garage and replaced the top mount and both sensor arms. Ever since then though, the rear end of the car has dropped to the floor overnight.
I then ordered 2 new airbags on the advice of the local garage and had them fitted.......this made no difference as the car still dropped after several hours of being parked. The garage had ruled out that the air lines were leaking which is why I was told I needed new airbags and when I pointed this out I was then told it could be the compressor or valve block!
Yesterday evening I started the car and it raised to the correct height. I then crawled under the rear of the car and coated every part of the air lines that were visible and accessible with soapy water and a handheld pump action sprayer. I stayed under the car for about 20 minutes in the hope of seeing a leak but nothing was visible at all. I also coated the valve block by the rear bumper with the soapy water and gave it a few light taps but still I couldn't find the leak.
This morning I glanced out at the car and was shocked that it HADN'T gone down at all! All I did was coat the air lines and valve block with soapy water and tap the valve block with a torch a few times. I've taken it out for a short drive and it's been parked for around 3 hours - usually by now the rear wheel arch is level with the top of the tyre, however it is still staying up!!
I've ordered a new valve block from Miessler in Germany and when (I'm not vey optimistic it's been cured permanently) it goes down again I'll replace that. Hopefully that'll be the end of the problem......if not then I'll just have to take to a Mercedes indi as the local garages are no use at all.
I'll let you know how I get on anyway.

 

[StuRox]

It is a puzzle to say the least, as its not playing fair... Either go down all the time, or stay up all the time

 

[Arkangel187]

Update: Apart from a small 10-15mm drop on the passenger rear side, the car didn't drop again last night.

 

[UkrainianHype]

could be an issue with level sensors?