2007 W211 Estate - Rear Air Suspension fault?

[Any_Name_You_Wish]

Morning everyone,

2007 W211 Estate - I suspect my O/S/R suspension airbag is failing. Leave it overnight and it's fine. Leave it a week and it sags so much that the tyre is concealed by the wheelarch. Start it up and it inflates (fast enough to feel it) and I had the N/S airbag and pump both replaced 18 months ago.

So, 1) is this what you think it is 2) how tricky a job is it? Youtube makes it look straightforward - I am ok at doing stuff myself (didn't last year due to illness) 3) Where would you get the parts from while everythig is shut?

Image attached - it's usually lower than this

 

[steveq]

Was the NS airbag replaced with a genuine MB one?
Then you should replace this one with an MB one too. Mixing an MB and a non-MB (or any different brands) on the same axle wouldn't be great.

I haven't replaced S211 air suspension units but I have done the job on an S212. It is doable as a DIY job but, like al DIY work, you need the right tools. Some of those suspension bolts are very tight and need breaker bars. The original S211 setup had aluminum reservoirs (I think) and the non-MB parts did away with them.

Also, before you head down the path of replacing the suspension unit, check the level sensor under the axle to make sure it hasn't broken / corroded away.