alltat2ed

I'm no mechanic so hopefully I can explain this right. I have a 96 cbr900, all stock mechanically. While i was riding today my back brake was making a grinding noise. When i got off and checked it the bolts were tight but i could move the caliper around. So I removed the caliper. The two bolts that hold it on seemed to be fine and the threads were intact as well. As i looked closer at the lower bolt that actually bolts to the carrier i noticed that the "sleeve" on the caliper, that the bolt actually goes through, could move in and out. But it could also move around. This is why i could jiggle the caliper when it was still on. I know there are floating calipers that move around on the rotor but i dont think mine is supposed to move like that. I would appreciate advice please.