The popping sound could be a couple of things first off is your wheel tight? check lug nuts. Some of other causes may be damaged rotors and pads. check them by removing wheel and looking for damaged parts or worn out pads. other things could be front wheel dive axle CV joint but you would hear this when turning also.
what would cause a rubbing noise on drivers side front wheel especially when braking ( I replaced rotor and wheel bearings are good) ?
not usually. warped rotors will cause a vibration during braking.
A front popping on the left of a 98 Blazer could be the brakes, steering, or wheel bearing. Check all three to find the cause.
warped rotor
replace front brake rotors and pads.
To the FRONT of the vehicle
What percent of braking are front wheels responsible
front struts berings
realignment, 60 to 80 bucks
One cause of a popping noise from the front end while backing up in cold weather is the drive shaft. A mechanic can help find the problem.
The pads may be worn out. have it checked out.
If it is a front wheel drive sometimes a bad cv joint can cause a popping sound when you are turning.