Airmatic leak on rear of 2010 212 - any thoughts?

[Londonscottish]

Hi all,

For a while the rear of my 2010 212 has been dropping very slowly when I've left it parked up for a while. It was originally barely detectable but now is getting more pronounced after, say, a week or so. So it's presumably leaking somewhere.

It's my local indy on Saturday for a service and they are going to have a look.

Anyone got any insights as to the likely culprit? I suggested the pipework. They suggested the air spring itself as they've seen them fail before around the perimeter.

Anyone got any suggestions as to what to look for and how?

I'm presuming they'd use some sort of soapy water/gas leak detector fluid?

Ta

 

[Londonscottish]

OK so the Man On The Internet says it could be the lines, the valve block, the air spring or the reservoir (if mine has one of those).

There are some diagnostics in STAR but a lot of it is down to soapy water.

Hmmm....wouldn't be st all surprised if it's too small a leak to detect at this stage. It didn't appear to drop at all last night.

 

[zipdip]

Nothing worse than a very small leak to find on these cars,also the airmatic systems on mercedes cars are all different,my S has a pump supplying a small tank from which air is used as needed,the E series are different as are the estates,hope the indy finds the leak for you,he will have the advantage of having the car on a lift so just maybe tightening any unions might solve it.

 

[bob6600]

Soapy is the best way to start - it's (virtually) free!

 

[Will]

It could of course be any of those things mentioned, but my guess is going to be the air springs themselves.

Had both replaced on my 2011 E63 last year. Funny enough the issue became more noticeable as the colder weather set in.

New air springs fitted and it never dropped at all even after being parked up for a week plus on occasion

Worth a quick search on the forum but this does seem quite common on these 212s with air at the back

 

[steveq]

Hi,

I would try the soapy water test all along the pipework and the valve block (which is under the back bumper).
I would be suspicious of the air suspension units. They are almost 10 years old (assuming they are the originals) and are under very high pressure. The rubber perishes and cracks.
I would suggest that you should measure the gap from the wheel arch to the ground on each side after 12, 24 and 36 hours (or more) of non-use to see if the car is dropping. I doubt if just a visual check will be accurate enough unless they are completely down.

You would need to replace them in pairs -- either use genuine Mercedes parts or use non-Merc replacement units which are a lot cheaper. It is possible to replace them on a DIY basis.

 

[Londonscottish]

It could of course be any of those things mentioned, but my guess is going to be the air springs themselves.

Had both replaced on my 2011 E63 last year. Funny enough the issue became more noticeable as the colder weather set in.

New air springs fitted and it never dropped at all even after being parked up for a week plus on occasion

Interesting. That was the off-the-cuff diagnosis of the Indy when I described the issue.

 

[Londonscottish]

Hi,

I would try the soapy water test all along the pipework and the valve block (which is under the back bumper).
I would be suspicious of the air suspension units. They are almost 10 years old (assuming they are the originals) and are under very high pressure. The rubber perishes and cracks.
I would suggest that you should measure the gap from the wheel arch to the ground on each side after 12, 24 and 36 hours (or more) of non-use to see if the car is dropping. I doubt if just a visual check will be accurate enough unless they are completely down.

You would need to replace them in pairs -- either use genuine Mercedes parts or use non-Merc replacement units which are a lot cheaper. It is possible to replace them on a DIY basis.

The car has deffo been dropping on the N/S rear for 2-3 months.

It tends to sit from one weekend to the next.

Last Saturday it was slammed at the back on both sides after a week's inaction.

It's getting worse :-(

 

[Londonscottish]

New Arnotts are £400 a side from ECP. Twitch.

 

[ChrisHGTV]

I had one side replaced on my 2011 E250 S212. Mine would drop a little on one side. It was the bellows. Cost was around 400 GBP fitted from TM Motors in Molesey (weirdly my pound sign is now a $ on my keyboard!). At the time I asked if it was worth doing both and they said there's no advantage - just do them independently when they fail.

 

[bob6600]

I don't think there is a benefit in changing these in pairs. I have just changed one of mine as it was dropping. I could have replaced just the 'bag' inside but it meant using a non-OEM part and the car being off the road for longer than I could do with. £400 for a corner isn't bad for an Arnott, I wish mine were that cheap lol

 

[steveq]

Hi,

I would suggest replacing both sides as a) they are both the same age so equally decayed and b) I suggest using non Merc replacements as they are much cheaper. The non-Merc parts will probably have different characteristics which might impact the handling if only one side was replaced.
The OP is saying that it was down on both sides which would say that both are leaking and need to be replaced.

By the way, I replaced mine almost 3 years ago with Aerosus parts. No issues since then.
I see that they are offering suspension units for both sides of the S212 for £369 (see Mercedes-Benz E Class W212 S212 Rear Left Air Spring (Bag) - A2123200725 | Aerosus).
-- No links just a satisfied customer.

 

[Londonscottish]

Hi,

I would suggest replacing both sides as a) they are both the same age so equally decayed and b) I suggest using non Merc replacements as they are much cheaper. The non-Merc parts will probably have different characteristics which might impact the handling if only one side was replaced.
The OP is saying that it was down on both sides which would say that both are leaking and need to be replaced.

By the way, I replaced mine almost 3 years ago with Aerosus parts. No issues since then.
I see that they are offering suspension units for both sides of the S212 for £369 (see Mercedes-Benz E Class W212 S212 Rear Left Air Spring (Bag) - A2123200725 | Aerosus).
-- No links just a satisfied customer.

Nice to have that as an option thanks.

To clarify, what started as a drop on one corner at the has developed into a drop at both sides.

I'm assuming that all the "rear air" is escaping through one leak.

Hopefully I'll find out on Saturday where the leak actually is.

The good news is that at least I now know that there are a number of options if it turns out to be the air springs/bags/whatever you call them.

 

[Londonscottish]

Hmmm.....no obvious leaks showing on any of the accessible lines/connections.

He reckons that the only way to get to the air springs themselves and the is to do a partial strip down - does that sound right?

In the meantime he's going to get some prices for the various different versions. Aerosus bags seem to get decent reviews. The struts less so.

Although if he can get Arnotts for a decent price I might pay the premium.

 

[MercedesDriver]

But, what if the bags are fine and the actual air leak is somewhere else or even non existant?
I’m only saying this because I’m in very similar position like yourself and the indy couldn’t find any air leak. It’s been like this for the last couple of years. Sometimes it drops sometimes it doesn’t and now after fitting new level sensors have started thinking that the dropping is related to the battery voltage. I have noticed that after long holiday trips it wont move one mm but if driven only on short commutes it will. The other thing is that it looks like that the entire SL system is determined by the voltage. Level sensors setup for example is programmed not by the height or any other length measure but by the voltage, at least that’s what I’ve found on the net.

 

[Londonscottish]

But, what if the bags are fine and the actual air leak is somewhere else or even non existant?
I’m only saying this because I’m in very similar position like yourself and the indy couldn’t find any air leak. It’s been like this for the last couple of years. Sometimes it drops sometimes it doesn’t and now after fitting new level sensors have started thinking that the dropping is related to the battery voltage. I have noticed that after long holiday trips it wont move one mm but if driven only on short commutes it will. The other thing is that it looks like that the entire SL system is determined by the voltage. Level sensors setup for example is programmed not by the height or any other length measure but by the voltage, at least that’s what I’ve found on the net.

Interesting......I had a new battery fitted in July 2018 but it will have taken a bit of a hammering recently as, bar a couple of runs out to Oxfordshire, it hasn't been anywhere since August. Maybe it's worth getting it tested.

The car is definitely dropping, though.

Hmm......

 

[DrNick]

Mine did the same thing (only has air at the back though - an estate version) and it was a very small leak in a connecting pipe and was difficult to find. Car was only 4 years old though so unlikely to have been the springs, to be fair. I suppose the point is, don't immediately assume its the springs themselves - they are an expensive part of the system.
Started off on one side only and slowly developed to being both sides. Only one leak though, on the side that originally went down IIRC.

 

[Londonscottish]

Mine did the same thing (only has air at the back though - an estate version) and it was a very small leak in a connecting pipe and was difficult to find. Car was only 4 years old though so unlikely to have been the springs, to be fair. I suppose the point is, don't immediately assume its the springs themselves - they are an expensive part of the system.
Started off on one side only and slowly developed to being both sides. Only one leak though, on the side that originally went down IIRC.

It's no doubt a pipe or the spring on the NSR.

The car is nearly 10 years old and so spring failure more likely that on a 4 year old one.

In either case I'm in for the labour to strip it gain access.

I'll wait to hear what he suggests.