Graber i3 Day 7:

Graber i3 Day 7: X-Carriage
I was not that keen about the zip tie fixation between timing belt and X-Carriage. Now I got another solution: Graber i3: X-Carriage beltfix by enhydra - Thingiverse

The lead screw touched a screw (see Pic #6). So I had to replace it by a shorter one and zip tie the “W” plate.