Some frames are difficult. My old Orbea has molded in cable stops, with a tiny hole in the center, just a little larger than the wire cable itself. This would never work with gravity, or a vacuum cleaner & thread.
The
best way is to push some
temporary thin tubing onto the existing wire from the back end. It makes a guide through the frame. Push the new cable through the tubing, then pull the tubing out the back.
See my summary post
here.
And more details
here.
The tubing: