Back in the day cable housing came with teflon lining that was inserted in the outer housing versus being built in. Your looking for a piece of that inner teflon housing. Good luck.

Your best bet is get a fairly good sized magnet and place it just in front of the hole to guide the cable through. I was able to do my Aluminum Klein with bis kitchen magnet. Obviuosly you want to pre-measure the cable so you know its about to get there.

Jim