WTK: knocking sound when i apply brakes

[Tisha]

guys, sat i changed rotars and disc pads, and now i am hearing a loud knocking noise every time i mash the brakes......what could cause that?

[Mr. Fixables]

This may sound petty, but did you check to see if everything is tightened back properly? People often forget to tighten the center nut, quite easy to forget that in the re-assembly process.

Kirk

[D AOK]

Your calipers probably needs servicing.
Had a similar noise and servicing the calipers did the trick.