S211 E55 rear air suspension

[Simonkey7]

Hi All, I need some help/advice.... I have an 05 S211 E55 and the rear suspension has been dropping overnight for quite some time so I have bitten the bullet and decided to have it sorted. My local indie is a good garage and have always looked after me well but we have now reached a point where we don't know what to do next...
All airlines were checked first but no leak could be found, Rear bags were then replaced with new, problem still persisted, thought that as it had been dropping for a while the compressor may be the issue so that got changed too... Still no joy... airlines and valve block were changed next just in case we missed a leak, problem still there... all reservoirs were removed, checked and hose connections cleaned up and re-checked... Still no change...
Now we're all scratching our heads wondering what could be the issue... any suggestions that could point us in the right direction?

 

[lukjur]

have you serted it yet ?

 

[ChrisHGTV]

I feel your pain! I ended up changing everything on mine, though my S212 doesn’t have reservoirs. What i did find useful was to really accurately measure the drop each side every couple of hours over a day (to a fixed point on the wheel arch) and then I plotted a graph of time vs drop. On mine both curves were almost parallel but not quite suggesting the leak was on one side only rather than somewhere that feeds both sides (such as the compressor). I think when one side drops is does seem to pull the other side down a tad which makes it tricky to pinpoint where the leak is. On my graph you could see the left was dropping more but very slightly. Turned out there was a tiny leak in the airline at the join on the left side.