2010 E350 S212 Rear Airmatic leak

[Tearaway107]

Hi Guys

As title, our S212 has had the infamous rear suspension dropping overnight when the temperatures are very cold.

Checked all pipework - ok
Replaced airmatic valve block behind the rear bumper with a new part to rule it out - made no difference

The suspension drops uniformly (not one side) so i need to rule out the pressure relief valve (which i think is on the pump / compressor). Is it feasible that we have a bad pressure release valve - and is this part replaceable on the pump?

Before we replace both rear air bellows which are very expensive i want to be sure that this pressure release valve is not the source of the problem

Thanks

 

[BlackC55]

It is not often that valve. I have not ever replaced one.

You probably need a pair of bellows. We change the pipes at the same time to be sure. We do many many of them.

 

[Tearaway107]

Thanks. That helps but what perplexes me is that the car never drops on one side - equally across the rear which makes me think that it's something other than rear bellows. Just want to be sure as the last thing I want is to change the rear bellows at great expense only to find it's a pressure release valve or pipe

 

[BelfastBill]

Hi my W212 is doing the same, some tines it will drop in an hour and next day it's ok for a few days. Now surely if there is a leak it will always be a leak and keep settling the same way. So I'm thinking is there something that controls the air pressure? could it be the air pressure reduction valve??
Thanks for any help,
Bill.

 

[Tearaway107]

Bill,

After much head scratching we opted to have both rear air bellows replaced. We took it to a Mercedes Specialist who had the car for a few days to monitor it and they said it was within spec but i told them to replace the rear bellows and the rear pipes as well as we tow a caravan and i don't want to have any issues This was done months ago now - and the car has been A1 since with no dropping overnight or after a few days.

 

[BelfastBill]

Thanks Tearaway, I will keep researching for a few days more, can't really afford new airbags at present as due to Covid I have been out of work for a while.