My mechanic lost the mounting nut. Its pn 68032913AA and this what size in the real world

 

That part number is for the cap and it's discontinued. Not the nut. Your mechanic can't figure it out?

 

Blame the Dealer service manager for that. He got the number (obviously the wrong number) off his screen. Need the nut that holds the wiper arm on. Nearest good parts store is an hour away. The nut is an M something or other. Could be worse, NATO stock numbers are worse