Detecting sticking front brake calipers

Ah well, I've learned that, if you cant easily retract the piston with a piece of lumber between the old pads and prying back, or using a vise grip big C body clamp, there's gunk in there that are likely to cause them to hang up.

Probably NAPA or the parts jobbers that shops use. But I'm not sure it's worth the effort. Since you'd need to get a cylinder hone to do the job right, anyway.

Price the calipers?

Bleed system First (before installing new/rebuilt)- till fluid runs clear

Does that hot brake smell mean for sure I need to rework/replace the calipers? I'd like to avoid this until after the winter if I can. The piston retracted farily easily with the big C clamp. I didn't try anything besides the C clamp to retract the pistons.

Well, only taking the pads off and inspecting might say for sure.

Perhaps you got oil or brake fluid on the rotors

Other possible causes.. been cases of degraded flexible brake lines causing "one-way valve' effect

There's also the possibility that there has been a buildup of rust (or dust, crap, whatever) where the pads or caliper is meant to slide.

If the pads or caliper is binding on it's slide points, the piston could slide in & out of the caliper easily and you could still have binding brakes.

Check your contact points are clean (ideally lubricate the steel on steel with anti-sieze and the rubber on steel/chrome with silicone grease. push the piston back out a bit, put some silicone grease under the boot (to keep it working well) re-install and ensure that the assembly slides easily.

Or, new calipers, new guide pins (if it has them) and clean and lubricated slides.

If the piston is moving ok, probably just needs a clean and lube.

PS it's always the little things that cause the big problems (NASA's "o" rings etc....)

Did whoever turn the rotors leave them with a rough finish? This would cause heat build up but should settle after a couple of hundred miles. Are you using softer pads? Can you spin the wheel easily if you jack it off the ground? Has you fuel consumption gone up? Have you lost performance? Do you drive like me?

Being too hot to touch is normal, that's it's job, to generate friction. Watch any race or rally car or the next 'plane on landing, especially in the dark and you'll see the rotors glowing. A smell is expected after replacing pads/rotors until they bed in (or you drive like me!)