Cat Twenty Two Final Drive Fill Plug

Greetings all:

  We have had trouble finding the special wrench or socket to service/fill the final drives. The plug has about a 1 3/16" internal hex. Could not find it in the 1952 Cat service tools book. Not in the tool list for the fifteen or twenty two. How does one get these off? Any thoughts would be greatly appreciated.  

Use a standard bolt, I believe about a 3/4" or whatever head fits in the hex and either double nut or weld a nut on the threaded portion of the bolt and use that. Not fancy but works fine.

yep thats all my bung spanners is a old nut welded to a old open ender that fits a square head bung elsewere on the machine.