I had to replace my shaft with a new a/t 17-4 and i have had this thing for years and never used it due to the grooves in the shaft from the rope packing. Got a new shaft and pump disassembly is a regular task for me anyway so I guess what I need to know is do they work or is the rope the way to go?
I'm real happy with mine. I instaled it when changing shafts. Have ran it for about 1 1/2 years now and it works great with no problems. I can't see running a rope type seal on anything, but on the other hand I am about as rookie as it gets with jet pumps so take it for what it's worth!