Hyundai Repair: 2004 sonata, rotor surface, caliper

Question
i have had my breaks repaired but now when i tap on my breaks there is a knocking noise - it doesn't happen if cold only some of the times when the weather has gone above freezing.

Answer
There are three common things which tend to cause a knocking noise when braking:

1.  Pads too loose (poor fit) in caliper.
2.  Caliper not securely mounted to knuckle.
3.  Uneven rotor surface.

You should return the vehicle to the shop that repaired the brakes and ask them to investigate the noise.