Originally Posted by scot68
Chrysler changed the wheel bearing assembly in the 1999 model year which is why the rotors are different.
No, they changed from a composite cast iron rotor with a stamped steel rotor hat to a full cast rotor in/around mid 99.
In 2000, they fixed the mistake of the incorrect registration hub for the rotor, and the amount of hub that protruded to center the factory rims on.
Once that was squared away, they then moved the whole mess closer to the knuckle to compensate for the thicker rotor hat. That put them back to the published track width specification.
The caliper is the same from 90-06 for the YJ, TJ, MJ, XJ, and ZJ as are the brake pads.