Did you use disc brake quiet[silicone goop] when you did the brakes? If not take them apart , use it. It'll work wonders. Or did you use metalic pads? they'll squeak forever. XJs call for semi-metalics but my own personal thing is organic pads, you have to change them more often but they don't squeak ,the dust isn't as bad, & your rotors last longer.I know rotors are cheap, thats not why I use them, it's the noise. A lot of people don't like organics, it's just my preference.