Give 1 turn loose when they stop then try.
If that help... Just lube it/them.
Ball bearing, hidden on top of adjust screw at bottom end of unit likes to bind and need cleaning and oil.
Be very carefully or it's easy to lose the bearing.
Do Not torque the bearing. Motor shaft does have a bit of play.
See my Cave, Gen 2 HL Motor
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)