In order to retract the rear caliper piston, you will have to use a special tool.
This tool will line up with the notches on the face of the piston. Then you will have to turn the handle of the tool to retract the piston back into the housing.
Here is helpful video:
I have attached the pad replacement and piston retract procedure below.
Please let me know of any questions.
Images (Click to enlarge)
Friday, October 8th, 2021 AT 4:03 PM