Quiet One Pump Cleaning

[aquamax]

My quiet one pump stopped working so I took it apart and now I dont really know what to do. I can't seem to take out the impeller which is a yellow one. Do any of you guys know what to clean?
Pictures can be posted if needed. Thanks You.

[aquamax]

At first I couldn't even rotate the impeller but after twisting it really hard I can rotate it pretty easily now. The thing that worrys me is some rust that I'm seeing on the bolt looking thing in the middle of the shaft. Well my question now is that is it possible to pull out the impeller and the shaft so i can clean it better?