Finally Ι got the gearbox out and what i did , i pushed the bushing a bit in to the point where it does not interfere with the camplate, and put a metric 3mm thick o ring (instead of a 2,6 mm stock) and some silicone. The silicone will break for sure bur i have the feeling that it will stick to places that the oring would otherwise leave a gap.
Now the camplate shaft does not have an end play to break the seal and i believe i will have no leak or if i do i will have a very small one. I did the same to the quadrant spindle also because i felt it would leak later on, it was kind of "wet" on the outside. We ll see when i test ride it but it seems sealed now.