Please forgive me if I missed this somewhere else in my search. I did search the entire site for "caliper rebuild" and just could not get a great example of how to deal with these knurl-in type pistons.
I've recently inherited my mother's 1988 Nissan Maxima automatic that has only 58K mi. on it and it is in overall "good" mechanical condition, and "fair" body condition. When I got it the brake lights would not go off, and the RR rotor was making a loud scraping noise, which I assumed was the pad sensor. So I tried adjusting the brake light switch, and this didn't get the light out, so I removed/disconnected it. I went to replace the pads, and long story short, I think the brake light and the scraping sound may just have been a seized piston, as the pads were plenty thick and the scraping could not have been the sensor.

Now I need help with deciding to rebuild the rear, twist-in type of calipers, or find compatible(s) at a junkyard, or just buy new or better ones. I could use some instructions/advice, but I think the dust boot and square-cut seal, should be replaced, just don't haven't found much instruction on the rest of the seals, etc.

Thanks in advance!

You'll be way better off just replacing the caliper - They're not expensive, check your local auto parts store.

The brake light problem is puzzling, but let's get the brakes actually working right, first.

Yes. I'd agree if these were the $35 type, but the lowest I can find new ones is for around $70.00 which is like 20% off at Advance Auto sheesh!
I would really appreciate any info you could provide or assistance if you're very familiar with this type of caliper rebuild. I would opt to replace them 1st too, if in the $30-$40 ea. range, but these are $70.00 ea. or more everywhere I've looked. If you can help, it's much appreciated, I've removed the dust boots and the square-cut seal from the bore, but would like to look at the procedure to replace the remaining parts as well, hopefully so that I'm not here again due to freeze/seize or other failure due to contaminates still down in the caliper. Junkyard calipers present the same concern, as I wonder how replacing my 23 year-old caliper with another one that's nearly or just as old will fail sometime soon thereafter.