Finally I got the PLA stick to my heated bed (50°C) with the use of Elkos Hairspray for 0,90€.
After the first layer my prints went off on the x axis. See picture below. My filament hangs just there as it is a 5m long piece I cut off the big spool. After holding the filament on level with the printer the print went ok again. I think this is due to the force the hanging filament put on the extruder.
It seemed that this was not the problem for the misalignment of the layers. The original y-drive is a very fragile design. It easily loosens and this is very likely the problem. I kind of fixed it with popsicle sticks and CA glue. CA glue on screws….nuf said.