I replaced the needle threader on my Pfaff 2040 Tiptronic a few years ago when I bought it used. The original owner wasn't a gentle person, and it was broken when I bought it. Now I don't remember how it went on for sure---I think the assembly may have just slid up a rod (?)---but I was able to do it myself. I think I was unsure at first and consulted with my husband. It wasn't hard, I know that. You do have to be careful when using it that you don't bend that fine wire, or tear it out altogether, which was the condition in which I bought the machine. I am always careful when using mine, and I've not had to replace it since. Mine doesn't automatically line up with the needle hole, either, since I put the replacement on, but it's not a problem. I just have to lower the needle a bit and the wire pops right into the needle's hole.