ABC (Active Body Control) suspension has long been the subject of a general “avoid” stigma. It is, of course, true that the system is interestingly complex and when malfunctioned and worn, guaranteed to be fault magnet. But I have to say that being in good condition is a pretty great system.

It just happened that, s500 w220Mercedes with code 487 (ABC suspension) option, came into my possession. As the autumn cooled down, the scary ABC warning text then lighted up on the test board screen. The diagnostic indicated a lack of operating pressure. The reason for the lack of pressure was easy to determine as the broken pressure pump because no drop of fluid was goming from the tank return hose.

(More about this equipment and w220 body can be found on the very versatile website: https://w220.ee/ABC)

I researched online, watched videos, and decided to order a new Chinese copy of the tandem pump for testing (the same unit has two separate pressure pumps: suspension and power steering). The pump arrived and a few days ago it was possible to dismantle the old pump. It was quite dirty work, because the hydraulic fluid and engine oil had spread to the left front corner of the engine compartment in good time and over time the oil had collected dust, making working less comfortable.

I will not begin to explain the pump dismantling itself. There are several instructions and pictures available online. For example, there are quite a few videos at the bottom of the list on the youtube link below. The creator has the compressor version of the w215 amg, so there’s even less space. https://m.youtube.com/user/jolypg

To be continued…