I've got a 2005 w639 viano and suspect I have a fault with the rear suspension. It looks to be sat too high and is quite bouncy in the rear end. I suspect it may be bouncy due to the bags being over inflated. I can lower it using the switches inside the tailgate, it goes all the way down and back up and I can set it so that the ride height looks right but it goes back up once you start driving. I've looked at the height sensors and they are connected ok. The compressor also kicks in when you load the car so that's working as it should. I was wondering if it can be calibrated or if there are still adjustable link rods available? I can't find any online. Any help appreciated, thanks.