Board Thread:General Discussion/@comment-1056021-20151017132537/@comment-6881629-20151017135943

Like the bugs list says if Haknir is killed early you can't get the armor as it breaks the quest, if you haven't tried it yet try reading the book but the quest will probably get stuck after finding the helm if it starts at all. As your on a PC you could spawn the armor with -

player.additem XX02401B 1

For the helm and the id for the other pieces are here (the XX is the load order of your Dragonborn).