I have a 2008 R350 4matic. The rear lift gate auto closes and opens. The raising, lowering and locking all work well, except when it closes the top of the drivers side of the lift gate seems to stay up about 1/2 inch. this causes it not to seal. How do I adjust this???

Check the hinge brackets that hold the tailgate. If the tailgate has shifted relative to its original position, you should see some evidence of that,like slide marks or so. This would be caused by loose screws, and you just need to readjust and tighten down again.

If that's not the case, check the stops or if something is blocking the tailgate. Otherwise, it could be a problem wit the strut or hydraulics.
Rear Tailgate Adjustment Screws - How to Adjust? - Mercedes-Benz Forum

https://m.youtube.com/watch?v=F6dTrnslLSA

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Prost!

Thank you so much for the response, I will check it as soon as my wife get home with it

adding some pictures

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I can't see where any of the screw have slipped, were you thinking of the area where the top metal holders connect or the locking mech???