If there is a clay leakage problem on the top of your extruder, you need to adjust the position of the coupling, increase the distance “a” between the coupling and the motor in the figure, and let the coupling press the silicone gasket. As shown below:
At the same time, it is also necessary to ensure that the motor and the extrusion barrel need to be tightened, so that the coupling can press the silicone pad, but it should not be tightened too tightly, which will easily cause the motor to block.
At the same time, you can also choose this plan:
Here is what I do: twist the stepper motor onto the black plastic body by hand till it stops rotating. Back it off 1/4 turn. You will need to clean the clay out of the black plastic part above the silicone washer. The soft/hard is a different issue.
Okay, let me know if I understand it properly. I will tighten the Black body and stepper motor so tightly that it doesn’t rotate, after that, unscrew it 90º so that it starts to rotate.