I could not get the hinge pin to slide out at all on the 650, so I just disassembled the plastic bits around the wheel enough to get at all the screws on the gear housing.

If you are wondering if this will solve your problem: I confirmed that this was causing a problem because I saw that the metal axle at the center of the wheel was recessed back from being flush the surface of the wheel “hub”. The hair and plastic tag strings had slowly forced the wheel off that shaft so it was rubbing against the side of it’s space and wouldn’t turn properly.