Hello! After I removed the rear wheel from a bike with a Shimano Nexus gear system to repair a puncture, I am having problems reassembling the rear wheel and its gear system: After screwing in the black screw (framed in yellow in the photo), it can be turned further without resistance. The gear shift can be easily removed from the wheel nut (pink arrow in the photo) instead of being firmly seated again.
I have repaired punctures on the same wheel before, removing and refitting the wheel in the process, but have not had any such problems.
I have not opened the gear box and cannot see any obvious damage. Any ideas what could be wrong?
There needs to be enough of the axle showing for the bell crank to bite. What I had to do on my wheel was remove the washers from the axle so the axle nut could be tightened enough and expose more of the axle to the bell crank.
If that makes sense.