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How to Repair a Mercedes Airmatic Valve Block
How to Repair a Mercedes Airmatic Valve Block
If the mercedes airmatic valve block fails, the AIRmatic with ADS system may not be able to raise the car to the selected vehicle height.mercedes airmatic valve block In this case the multifunction display in the instrument cluster will show: "AIRMATIC VEHICLE LEVEL SETTING CANCELLED" for a short time. The damper valves are then returned to their default hard damping level for driving safety. This condition can be corrected by changing the desiccant in the compressor unit.
The Airmatic valve block is responsible for distributing the compressed air to both rear air suspension struts.mercedes airmatic valve block It is also responsible for the height control of the front air springs. In addition it controls the air pressure of the compressor and central reservoir charge valve. The AIRmatic with ADS system uses a high quality electric compressor to generate the air pressure needed to lift the vehicle. It is fed by the AIRmatic Compressor Relay located in the right fuse box (location 'O', first one next to the three 40 amp fuses).
There are two mounting assemblies that need to be removed in order to open up the AIRmatic valve block. These can be loosened with four small electrical screwdrivers or wooden wedges and the Solenoid Pack / Cover can then be lifted off with help of a vice. It is then a good idea to douse the whole assembly with some PB Blaster penetrating fluid as these screws can have heavy corrosion on them. After liberal application it is a good idea to wiggle and jiggle the whole assembly until the two halves come apart. When reassembling make sure the larger solenoid o-rings are placed in the recesses of the metal block to prevent them from getting nipped or cut when the plastic cover clips back over the lugs on the metal block.
In some cases the high pressure line from AIRmatic valve block to the rear struts develops a leak. This can be difficult to find as the line runs through the interior and may only be noticed thanks to a loud hissing noise. The air line can be replaced with a replacement or with a M-B repair kit (5 ft length only). Alternative line can also be run from the front valve block to the rear to test the valve block to strut connection without dismantling the whole system.
It is important to depressurise the AIRmatic system before unscrewing any pressure line connectors using STAR diagnostics. The pressure in the line can suddenly drop and cause a serious accident. It is also recommended to mark the air lines BEFORE removal to avoid having to look up their designations when reassembling. Also, it is a good idea to plug any exposed pressure line ports with blind plugs immediately. It is also a good idea to cover the connectors in the AIRmatic reservoir unit with a piece of masking tape for protection from dirt and rain. It is also a good idea to change the silica gel in the compressor unit at some point. Moisture will accelerate oxidation of aluminium components such as the compressor unit and the valve block.
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