Without the manual I can't help you with that drum problem but I'm sure there are those that can help.
Just a few observations though, it looks pretty dirty inside your cases.
I could be wrong as it can be hard to tell from a computer pic but if there is any grit.... get it out now while you have the option.
Otherwise that stuff will go through your bearings and you'll be very disappointed.
Also, it looks like the bearings might be a bit rusty?
If so, now is the time to replace them...