remove nut using a wrench . There should also be a small washer but they usually get stuck inside , they should fall out during the next step.

Next this bolt will need to be tapped out . you can either LIGHTLY tap it with a wrench from the threaded end ( see last step) or you can use vice grips .

Once Bolt is removed the arm is now loose . It may require some hand force to detach it from the assembly .

Beware if you are working on the right side roller arm ( sitting position) there will be an extra sensor that needs to be unplugged