Some pulleys have hoods. I presume this was thought to prevent cold air from entering the house through the gap between the pulley and pulley housing (In fact, some hooded pulleys even have a ring of felt embeded in the hood and surrounding the rope.) The hood confounds conventional methods for feeding a replacement rope in place of a missing one.
To accomplish this, I use a couple of homemade fixtures – a length of fishing line wrapped around a piece of rope about 1 3/4″ long and secured with electrical tape . Also some metal wire that is both rigid and flexible and looped together.
Push the piece of rope into the hood opening.
Push the rope further around the pulley with the wire bundle. The wire bundle should coil around the pulley so the rope drops. Extract the wire bundle. Feed the fishing line into hood opening until you see the piece of rope in the opening of the weight pocket access door.
With masking tape, tie off the end of the fishing line to your length of new rope.
With an awl, nudge the rope into the pulley hood while gently tugging on the fishing line.