[rockdoc]

I would not hesitate to rebuild them. When I rebuilt my calipers, good-quality parts were very inexpensive. At the time, I found a supplier on Amazon, and I think they were clearing out their inventory. I bought their last 5 pistons (didn't need all of them) for something like $3 each. They are still available. I found the specialty tool for installing the pistons into the calipers for a reasonable price on eBay. The tool was definitely worth it (Kent Moore Disc Brake Caliper Piston Ring Compressor J-22591). You can do it without the tool, but it makes it a breeze. There's a couple on ebay right now for around $20. I rebuilt them in 2018 and they have been trouble-free since then. My '67 had the front disc option, BTW, so mine are OE. As gto4ben said, make sure you get the boots oriented correctly.