This Ni Nut-Lock, or Nylock Nut, is a Silver 1/4 x 20 metal nut. Sold individually, it can be adjusted using a wrench or socket and torque wrench to the manufacturer specfications, and is used to secure the sheer pin in place, on the impeller assembly. These nuts are a one-time use part due to their locking mechanism. You'll know the nut...Read more has broken when it appears to have damaged threads or rounded off edges.
Customers found this to be an easy repair.
The lock washer goes next to the flat washer and is made of metal. It is available as an individual replacement part. This genuine item is supplied by the original equipment manufacturer for use with snowblowers made by Toro and Lawn Boy. A wrench might be helpful during the installation of this part. This item may become broken and will need to be replaced.