Joe Mike Terranella published a video tutorial on how to change your direct feed extruder system into a Bowden 3D printer. He used his Hictop Prusa clone to change it from direct feed to a Bowden setup but you can see many useful tips that can be used for other machines also.
Here is the full tutorial video:
Full parts list is on the video description but he used this Bowden conversion thing:
Here is Joe's Twitter where you can follow him: