My prints show that I've an X axis wobling issue. It is too much that can be caused by the Z threaded rods (anyway I handled that originally):
I was "monitoring" the printer with my ear during printing.
Realized that the clicking noise is coming from the Z bridge assembly's right side. My guess is there is something went terribly wrong with the timing belt pulley.
I was right.
This "was" one of the tiny bearings inside the pulley:
I tried to find a similar bearing.
Looked in the box containing the original parts of the GeeeTech printer - they provided spare parts for some things - not this one.
Looked in my box of bearings - no this size
Looked around on the net if I can find what is the exact type. I was only knowing the physical size 8x4x3 mm. After some iteration and guessing I know the type: MR84ZZ
Ordered from Aliexpress. It take a while, so I was looking for a local source. Find it, ordered it.
In the meantime I wanted to resolve the issue to be able to print.
On the thingiverse I found a replacement pulley, what has no bearings inside:
I tried to print it out with only one bearing in the original pulley. It failed.
After a good start. I've a broken 3D printer. Again...