Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I would assume that the 'brake' inside the wheel is defective, for whatever reason.
But that might be a wrong assumption, perhaps.
And I regret that I do not know how to disassemble or service the 'brake' within the flywheel, so I have Opted Out again, in favor of another Expert or in deference to a more informed opinion.