The 2002-2012 Mercedes SL55 is built with the following suspension components:
2002-2012 Mercedes SL55 Active Hydraulic Struts (x4) - A long tube (similar to a shock absorber) that fills with hydraulic fluid forced in at varying rates of pressure determined by sensors on the vehicle.
The strut is a perch for a metal coil spring, which helps support the weight of the vehicle. The struts on this vehicle are considered "active" because they can be adjusted hundreds of times a minutes electronically. Much like a shock absorber, the strut dampens vibration and bouncing caused by travel on rough road surfaces.
2002-2012 Mercedes SL55 Height Sensors (x4) - A linkage located near each wheel of a vehicle that electronically measures the height of the vehicle, and reports this information back to the control module so that the computer can identify if changes in height need to be adjusted accordingly. The ride height sensor is a moving part, and like all moving parts, they will eventually wear out.
2002-2012 Mercedes SL55 Hydraulic Lines- Lines that carry fluid from a hydraulic pump to the vehicle's active struts in order to adjust the height of the vehicle.
2002-2012 Mercedes SL55 Hydraulic Pump- A mechanical pump that delivers hydraulic fluid to the active suspension components. The pump can burn up prematurely when leaks in the suspension system cause fluid levels to get too low.
2002-2012 Mercedes SL55 Suspension Control Module- A computer responsible for the operations of the active hydraulic suspension system and maintaining the vehicle's correct ride height.
2002-2012 Mercedes SL55 Rubber O-rings- Although they are the least expensive parts of the system, they are responsible for maintaining the seal where all of the hydraulic fluid lines connect. Bad Rubber O-rings cause leaks in the system and leads to part failures.