first, an oddity: when I got ready to remove a front rotor, I discovered metal shims at the base of two of the five wheel lugs. They were thin, O-shaped, and sized so they screwed on to the studs (kinda like a speed nut -- not really formed threads). What would these be for? (To make sure I'm being clear -- the shims were sandwiched between the rotor and the wheel -- not between the wheel and the lug nuts.)
They put those tinnerman's nuts (for lack of a better name) on at the factory - my guess is to hold the rotor on on the assembly line until the wheels get put on. They probably get rapidly pushed over the threads up against the rotor for production efficiency (rather than spun on like a nut). They get discarded the first time anyone removes the rotor. That means your car is running with the original rotors? Amazing if so. How many miles on your car?
Also on one of my front brakes, the caliper apparently stuck and ground down one of the pads to metal-on-metal contact (ouch!). I am replacing the pads and rotors (on both front wheels), but wondering if I need to replace the caliper. I've put it through a couple cycles, using brake pedal to push the rotor in, then a C-clamp to squeeze it back out. The caliper seems to operate smoothly in both directions, and does not require unusual effort to retract it. The rubber boot also seems to be intact, but the boots for the sliding bolts have holes in them, and I'll be replacing them too.
When I install the new pads/rotors, I'm also going to install the spring thingies referenced earlier in this thread, which should -- in theory -- reduce the likelihood of the caliper sticking.
So: Plan A -- leave the caliper as is, and check fairly soon to see if it's sticking. Plan B -- get a caliper repair kit for around $1.50 (which replaces the piston seal and the boot). Plan C -- get a new/rebuilt caliper.
At the age of these cars, I would recommend new calipers. You can try to loosen them up, but like I said, at the age these cars are, replace.
You could rebuild and save money, but for the time, trouble, and mess of rebuilding, unless you're really stretched for cash, I'd replace the calipers. I nursed the ones along on both my Concordes for a few years, but they started getting worse again, and exercising them didn't help anymore. Eventually, it's time to replace. Start your new brakes off with a clean slate. NAPA has some good calipers, and no more expensive than the off-brand stuff that Advance sells (at least that was the case when I replaced mine 5 or 6 years ago). I'd get, not their cheapest, but the next step up in price.
By the way, wear on the pads at the rear wheels was normal. I'm replacing the pads, mostly so that I've got the same ceramic material on all four wheels, but leaving the rotors and calipers intact.
Typical. The rear brakes don't see nearly the stress and heat that the fronts do.
Thanks again for all input. Also, point well taken from previous poster re getting rid of rust on all mounting surfaces. I had one wheel that didn't want to come off, and one rotor that put up a really good fight because of corrosion around the hub surface. Tried PB Blaster, heat from a propane torch, slide hammer, and finally succeeded with a bearing puller.
Ron's advice on getting the rust off may have had more to do with not introducing wobble into the rotors. Think about it: A flake of rust between the hub and rotor (on one side and not all around) is going to tilt the rotor, and it will act like a warped rotor. Let's say the flake of rust is 0.008" thick. At the diameter of the hub, the tilt gets multiplied 2 to 3 times at the outer edge of the rotor, so you'll have 0.016 to 0.020" of runout. You'll feel that in your brakes, and it adds additional wear and stress to your brakes and suspension.