W212 Backside drops

[davidjpowell]

We have a E350 W212. Until recently it has been reliable. It is now becoming something of an annoying teenager and nearly as expensive.

It has spent 3 days in the garage for 'stuff', where one of the things I wanted to sort was the drooping rear. It has come back with bigger problems elsewhere, and a diagnosis on the suspension that I'm not completely onboard with.

The rear drops most times, but often just one side. The side can vary.

The garage pressurised the system from the pump, and it did not lose pressure. They have therefore diagnosed the pump, believing there to be a valve that diverts air to each side. I thought however it was a single pipe that went out to a valve distribution block splitting out to left and right.

Any suggestions?

 

[ChrisHGTV]

It can be frustrating, mine was in and out of two Indy’s about 4 times before I got mine sorted! My compressor at 10 years old was leaking like a sieve apparently. I bought a refurbed MB unit but you can actually get rebuild kits much cheaper. The valve block is cheap to replace so might be worth trying that. Could be that the valve block is leaking then allowing pressure to escape back through the compressor? In the end I replaced everything that holds pressure. Not cheap but its been fine for a couple of years now. One thing I would suggest is replacing any airlines that you can, mine had leaks as well where they rubbed on the bodywork, and the leaks are difficult to find. Quite cheap to replace.

 

[Bobby Dazzler]

We have a E350 W212. Until recently it has been reliable. It is now becoming something of an annoying teenager and nearly as expensive.

It has spent 3 days in the garage for 'stuff', where one of the things I wanted to sort was the drooping rear. It has come back with bigger problems elsewhere, and a diagnosis on the suspension that I'm not completely onboard with.

The rear drops most times, but often just one side. The side can vary.

The garage pressurised the system from the pump, and it did not lose pressure. They have therefore diagnosed the pump, believing there to be a valve that diverts air to each side. I thought however it was a single pipe that went out to a valve distribution block splitting out to left and right.

Any suggestions?

These sometimes-but-not-every-time issues can be a bu66er to diagnose. If you’re not happy with the diagnosis then it’s worthwhile seeking a second opinion from another garage, ideally a well-respected Mercedes specialist to maximise the possibility of them being familiar with the system. Good luck sorting it

 

[Popell]

If it's one side or the other, that would suggest valve block problems rather than airbag.
Mine been doing it for a little while on LHS, changed the bag that side, good for a little while now dropping on the right (I bought a pair of bags but he job to change was such a b**ger that I deferred rhs till required.
What I did find was that there is clearly plenty of moisture in the system, presumably drawn in from the air by the compressor. The desiccant in there simply can't last the 11 years old that my car is, any how the recent cold weather must have frozen the water in the system and probably in the exposed valve block, preventing the car from lifting. Judicious use of a hair dryer thawed the block out and the suspension pumped up to normal, full dry out required when it gets warm enough to swap out the rhs bag.

I'd be interested to know where to get the compressor refurb kits if anyone has a link

 

[ChrisHGTV]

If it's one side or the other, that would suggest valve block problems rather than airbag.
Mine been doing it for a little while on LHS, changed the bag that side, good for a little while now dropping on the right (I bought a pair of bags but he job to change was such a b**ger that I deferred rhs till required.
What I did find was that there is clearly plenty of moisture in the system, presumably drawn in from the air by the compressor. The desiccant in there simply can't last the 11 years old that my car is, any how the recent cold weather must have frozen the water in the system and probably in the exposed valve block, preventing the car from lifting. Judicious use of a hair dryer thawed the block out and the suspension pumped up to normal, full dry out required when it gets warm enough to swap out the rhs bag.

I'd be interested to know where to get the compressor refurb kits if anyone has a link

I found this link on this site - i can't vouch for it as never used it. (Note this is for an s-class but assume they also do E class) I guess it also depends how the rest of the compressor is - the bore etc. For £20 must be worth a try though?

Mercedes S Class Wabco Air Suspension Compressor Piston Ring Repair Kit

 

[Popell]

I found this link on this site - i can't vouch for it as never used it. (Note this is for an s-class but assume they also do E class) I guess it also depends how the rest of the compressor is - the bore etc. For £20 must be worth a try though?

Mercedes S Class Wabco Air Suspension Compressor Piston Ring Repair Kit

Thanks for the link Chris, I’ll check it out this evening

 

[davidjpowell]

Thanks all. Gives me something to look at.

The suspension is a longer-term fix. First priority is a rusty rear subframe..

 

[R Phillips]

My W212 estate has started to drop, sometimes over night sometimes it takes a couple of days. It always looks to go down level.
Would that suggest it not a bag leaking?