I have this owner's manual and parts list, dated 1981 that was with my grandparent's paperwork when we sold their house. I no longer have the vacuum cleaner, but if someone can use these instructions and parts lists, drop me a line and we'll work something out.
Someone pointed out to me that this is a Singer made machine (of course Singer's designs were eventually sold to Ryobi in the 1980s, and Ryobi continued to make "315" prefix power tools for Sears for years).