Clunking noise when reversing

I've noticed this previously as well that when I reverse and lightly tap the breaks I hear a clunking noise . Same when I'm going forward. What does this mean?

 

It’s the brake pads shifting in the caliper. Nothing concerning.

 

Gotcha. I do need to change my front pads too so that may be part of my concern.

 

The brake grease gets gummed up from road debris. You need to pull pads, clean backside of pads and shims. Clean pad pins, re lube back of pads, shims and pins. Re install and you should be good. I do mine once a year.