there should be no back and forth movement of the rotor on the spindle, i dont know if you replaced the races in your rotor, but most new bearings come with the race that you can replace your old ones with and make sure you pack the new bearings with grease and grease all inside rotor and the spindle shaft thoroughly and replace the back seal.

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2002 black ranger edge supercab, 2WD, stepside bed, 3.0v6, 5 speed, 4.10 8.8 open, manual windows and locks but cold a/c and cruise Daily Driver..70 miles a day.
so far:
air box mod, throttle cable mod, sceptre highflow air filter