How old is it? Since it is a 510 it would have been made in 1950
To get the emptor open turn the handle on the side and swing the bottom of the emptor out. It might be stuck because of all the junk in the emptor.
The brush roll looks like there is enough rust and corrosion that the bearings are seized.
The good news is that the brush rolls are still available.
Part number 1482S for the brush roll
The belt is a 159056
If you need to replace the brush roll screws in the nozzle
the large screw is a 1461S
the small screw is a 1463S