Some of the parts on the printer are showing their old age and may reduce the quality. These are cheap parts to replace:

1. linear shaft 0.8mm
2. polymere bearer
3. gear belt
4. Z-axis stop
maybe more parts to come..

Resolving the leveling issue:

1. Z-axis stop
The z-axis stop is now a normal switch. It seems not to respond as expected. Therefor I will replace it with an optical stop which should be more precise.

2. In my case when the hot end pushes on the glas the horizontal shaft and bed bend a little. I'm not sure if it bends back exactly the way it was. Also it seems that the whole extruder is leaning forward a bit which could imbalance the printer. For this i want to change the horizontal x - ax shaft. See pic 1 and 2 (pic 1 is the way i want it, pic 2 is the way i have it)

3. autoleveling
Even if everything is in balance I know humans can't level 100% correct, although the paper method works quit well... For that autoleveling can be installed. This only needs a proximity sensor (4$ on ali) and a nice way to attach it to the extruder.

When al this is done I am considering installing the bowen construction. This will increase the quality of the print but not all materials are supported. Since i mostly print with PLA and ABS that may not be a problem for me.

external sources

Carriage facing down

Maybe usefull upgrades