RogersRacing, you say you have the alloy brake disk. Did you install it or was it installed when you bought it? The reason I ask is I installed the alloy disk and metal plug in my son's ATX and had binding issues like you described. The metal disk has sharp corners on it that caused it. I dremmeled the corners off and it got a little better, but I still need to work on it a little more. I plan on making it rounded instead of squared off. Just a thought.

Edit - Sorry, i did not do a good job describing it. If you need, I will see about getting a picture of the part I am referring to.