Hi all
New member here with a 2008 s550. I've been having a problem with the left rear strut. Over night the ride height will drop. I've checked the top of the strut with soapy water and no apparent leaks i also checked the distribution valve and no bubbles. I can see the pressure dropping in the live data on my scan tool but can't hear any leaks. sometimes the pressure drops very low but the car itself stays level.... i'm thinking perhaps the leak is internal to the distribution block? Is the pressure measured at the block or the strut itself? even when the car is fully level the pressure reading from that strut is 20-30 psi less than the others?
the car has 70k on it.
any help appreciated

You car has problem with the air strut and need to be replaced, over the time the rubber bag in side the strut is crake and damage causing air leak, either yo can buy a new air strut (it cost around 400$ -700$/piece depend on brand). Pressure measured on the distribution valve block located near air pump on the pumper of front right wheel.

Turns out the problem was a cracked line under the starter battery tray. easy fix. As a side note, prior to fixing this i would have intermittent problems with the blind spot detection system and i haven't had a single issue now i have repaired the suspension. I'm thinking with the car constantly listing to the left in the rear that my have thrown the sensors off....