Hello, so to get to the point quickly, my lift no longer goes up… Oil tank is full… So now the short story about it. I got a DDR Scherenhebühne 1.5to before 3-4 weeks ago. I set it up uasrichtet etc pp… tried.. so put on 20 sec. waited and then with a Kadett D also quite normal completely raised up to the penultimate hole.. went 1a also completely down 1a 1. does not have to be lockable to the last hole? So then 1 week late he … back to my hall stream ..and the stage went only half up still sounds like she can no longer go higher.. so again completely down.. then 1-2 minutes waited.. then she drove with trouble into the penultimate hole…but more not .. then last weekend .. and today… she it does not happen at all anymore when I want to lift… as promised oil is full of oil looks “urin” yellowish .. So what can I do .. where exactly is this “ventilation screw” has the operating instructions about … but there is not only a screw that could be the right one.. If more should be defective there are still ET parts ?? or builder/ten I hope there are some here who know about it.. at least more than I thanks to you already MFG Berliner