I'm a little late to this party, but it's true...you don't need to remove the rotors from the hub to resurface them, but if the rotors are shot(unserviceable), then you can drill the rivets. It's always best to turn rotors on the hub when they are made like that...it keeps everything aligned, and eliminates the chance of something getting between the rotor and the hub that will throw it out of whack once it's back on the car. You can have a rotor that measures perfectly for wobble, but gives you run-out when installed back onto the hub due to a small piece of doo-doo(tech term for rust) between it and the hub. Turning the rotor with the hub attached keeps the whole mess "true", spec-wise.
It's not the end of the world if you separate them, tho...it just leaves more room for a run-out problem.
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Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"