Any likely end play shouldn't make any noise at all unless it's hanging off!
If it only makes a noise when braking then it's something caused by the wheel rotation or moving parts of the brake system or as G says worn splines which clonk with power on/off.
First thing is to decide if it's front or rear I think! Can't think of anything likely to cause a 'popping' noise though, most are grindy, clicky noises caused by things like stones behind back plates or spring retainers come loose etc..
Last edited by SteveT; 23/02/17 01:11 PM.
