SRAM X.9 RD problems

I just bought an X.9 setup it was working grate until my last ride and I started to get shifting problems. My hanger was bent so I straightened it expecting to fix the problem. The RD does not want to return to the smallest cog. I inspected the adjustment screws and found nothing wrong. What I did find was that the knuckle was rubbing on the mounting bolt. This suspired me because the RD did not receive a big hit. I changed to SRAM because I though that they were fairly bomb proof, perhaps I was wrong. Has any one else had a similar problem?