Hi Bob, are you sure it needs to be drained? There really isn't a procedure provided for that process.
If, however, you are concerned, first prepare the tool being used to depress the piston. Apply a slight amount of pressure and open the bleeder on the caliper. While you depress the piston, the fluid will come out of the caliper rather than being sent back to the master cylinder. Actually, this is a preferred way of doing it to prevent dirty fluid from making its way back up the system.
Once the piston is fully depressed, close the bleeder.
Here is a link you may find helpful with the brakes:
Let me know if that helps.
Sunday, April 23rd, 2023 AT 8:52 PM