Keith, there is NO washer under the bolt head on either of my mule drives. The Parts Lookup listing of just one flat washer I believe confirms my suspicion that my spare mule drive has a washer between the adjuster bolt and the pulley bracket where it doesn't belong. It's possible that I accidentally put that washer in there when I put it back together after having the adjuster bolt rewelded (note the fresh paint on it in my earlier posts) It was apart for a week or so and I was working on some other Cub related stuff and the hardware might have gotten mixed.