I bought a used (and somewhat abused) 2003 Nissan Sentra SE-R Spec V about six months ago. I knew going into it that it needed maintenance… the previous owner had neglected much, it seems.
I’ve replaced the entire front end (Ball joints, CV axles, Tie-rod ends, and front wheel bearings).
Not long after that, the rear calipers siezed up… the dust boot had gotten twisted about and had made it unable to fully retract, or extend in a straight manner.
After replacing the calipers, I had the rotors turned to make it a smooth surface.
I’m suspecting the rotor might be warped, because, most audibly at slow speeds, you can hear a squeaking coming from the front right. This is why I think it’s warped: The rotor has one scoring that goes around the entire circumference of the rotor. On 1/4 of the rotor (approximately) right underneath that scoring mark, there’s another. It’s my guess that that second scoring is what’s making the squeak. As the rotor passes that point, it shaves off a little bit more of the metal.
All that aside… given that there’s no vibration in the pedal, is it feasible to let it wait until the warm weather? It’s really darned cold out right now here in TN, and I’m not looking forward to doing rotors and pads in the freezing snow…
How urgently does this need to be done?
When you replaced the calipers and turned the rotors, did you replace the brake pads? You don’t mention that, so I’m assuming you didn’t.
Rotors don’t get scored because they’re warped, they get scored because the pads eventually wear down to metal-on-metal contact with the rotors. How much material is left on your pads? Sounds like you need new ones. Or something else that shouldn’t be touching the rotor is touching the rotor.
If the rotor was warped, you’d feel the brake pedal pulsing.
You’re right… I didn’t replace the pads. The pads had plenty of material left on them… when measured, they had 90% of the material left, so we figured we could leave it be.
The only reason I was thinking the rotor was warped was the very strange cut in the rotor. One ring, all the way around… and on 1/4 of the circumfrance, a second ring approximately 1/8th of an inch. That’s why I wondered if it was a mild warp as opposed to something we could use to fold pretzels with.
Still, I’ll take another look. Could be some sort of pad defect that wasn’t obvious before, I suppose… that second cut on the rotor though is gonna drive me bonkers.
While I agree with Jesmed, You also might want to consider that you may have a rotor that is now too thin. Modern rotors don’t last much past one set of pads.
Did you check for rust on the hub flange?
If there’s a lot of rust on the hub flange, and you take off an old rotor and slap on a new one, the rust on the hub flange will prevent the new rotor from seating squarely onto the hub flange. This then causes rotor run-out where scoring of the rotors can occur.
Tester
It’s possible that some stray bit of foreign material got in there somehow and gouged your rotor before being ejected…maybe some small bit of something that got stuck on the pad when you reinstalled it. Whatever it is, it’s apparently gone now. I wouldn’t lose sleep over it, unless the gouge mark continues to grow, which it doesn’t seem to be doing. Just keep driving, and the gouge will soon be gone as the rotor wears down.
You can’t rule out wheel bearings either. I would not have said that previously but 2 years of brake checkups, all is fine, and a squeak every time I applied the brakes then I had a vacation emergency wheel bearing replacement, and the squeak went away.
They replaced the wheel bearings.
Tester
Good catch, after re read I see I missed it. That is what I get for the non Evelyn Woods speed reading class! 
A little rotor scoring is harmless in my view as long as the vehicle stops without pulling to one side and the brakes do not pulsate. I have always changed my pads safely before wearout to the rivets and still get rotor scoring or grooving. With enough grooves, you want to be gentle with the brakes after new pad installation until the pads wear to fit the grooves.
Disk brakes often have a tendency to squeal. Google this for more if it annoys you.