These there documents should help someone service their ElectroLIft units for the Meyer Snowplows. Neither has a date, but I would guess these are close to 1960.
There are two ElectroLift control types, one mechanical and one electrical, so make sure you know what type you have. This first form provides installation instructions for the mechanical type. It is Form Number 1-101. Page 2 shows only. a partial electrical diagram. I’m not sure why only the partial diagram shows.
This second document discusses the electric control type of ElectroLift. It is Form Number 1-311
This third document is Form Number 1-132R5 and it shows how to overhaul and service the units. These service instructions and troubleshooting apply to both the mechanical and electrical units: