Air suspension inflating one side

[Braincrank]

Hello all, please forgive me if this issue was discussed here before but I couldn't find any answers yet.
2 weeks ago I put the winter tires on my farther-in-laws Merc, a 2012 Estate with hydrolic air suspension ( don't know the exact model no.). Ever since, the rear right suspension is inflating which makes driving impossible. The rear left is normal and the rear right looks like a offroader. We did the old trick of putting weight on that side with engine running and when we take the waight out, the suspension is re-calibrating and adjusting itself and all is good and the rear right and left of the car is level again. But as soon as the car is driven, the suspension is inflating again on the rear right.
Could it have anything to do with jacking up each wheel, one after the other, so that it hangs down to be able to change the wheels, or maybe because I fully tightened the wheel nuts on that particular wheel before I lowered the jack (Normally I just tighten the nuts enough to hold the wheel in place and fully tighten them after lowering the car back down.)?
Any advice, hints or tips are welcome!

 

[Gbrowncls55]

If it has it its air suspension not Hydraulic. Get it on STAR that will tell you if theres a fault. If it needs recalibrating for some reason that can be done using star while its there.

 

[ChrisHGTV]

It could be something to do with the ride height sensor arm on the right hand side? Could it have moved or become loose during the jacking up? When i was investigating my suspension issues (suspected ride height sensor failure) i found you could make the suspension move by manually fiddling with the sensor arm (engine running). Im not suggesting you fiddle with it but if you can see it easily you might be able to see if there is something obviously wrong? On mine it's a small plastic arm with a ball joint at each end - couple of inches long.

(I actually had the same symptoms as you, but in my case it was that the Merc "specialist" had actually fitted the airlines the wrong way round in the valve block!). From memory if the sensor doesn't provide a signal i think it defaults to pumping that side right up, so maybe there's a dodgy connection or the arm isn't acting on the sensor properly?

 

[Bobby Dazzler]

My first thought is that the sensor arm has been disturbed. They have been made of plastic in the past and they had a tendency to bend. Metal replacements are available.

 

[Braincrank]

Thanks for all the replies!
Is it possible that I might have knocked it while lifting the wheel in its place? How accessible are these sensors? Do they just stick out somewhere behind the wheels?

 

[steveq]

The height sensor is in board from the wheel so it is very unlikely that you physically hit it while you were changing the wheels.
However the axle hanging down might have have overextended it and it disconnected or broke.
Here is a photo of one side.
It isn't identical to your FIL's car as it has coil springs but the sensor looks the same.

The plastic lever might have snapped or the little ball joint might just have disconnected.

You will have to get under the car to look. Be very careful moving the lever as the car will try to automatically adjust its height.