Mine did that at one time also. I checked it all out and saw no problems so, I just went on my merry lil way and it eventually stopped. If you have high performance pads they tend to make more noise than stock. Datz da souund ov stopping horsepower! As far as A/C goes.....R134A is R134A......it dosent matter as long as you have the proper oil and refrigerant levels which is not always attainable with those over the counter "can" recharge fixes. Usually if you need a recharge then there is a leak and adding more is just a temporary band aid.
Oh, and it's brake on a car not break. Not trying to be a d%#k.....its just a annoyance of mine.
06' wrx tr