City & Comfort - How to align a hydraulic disc brake caliper

A brake caliper's job is to squeeze the pads against the rotor to slow the bike down.  If the caliper is not aligned, the pad will contact the rotor and cause a subtle noise or even slow you down.  Mechanical disc brakes use a cable attached to the caliper to move the pad.  

 

This video shows all the steps to align a mechanical disc brake caliper.