nothing wrong with replacing the seal on a caliper once in a while, if that's all it needs, why replace it, besides I would rather rebuild something than replace it any day,
that way I know it was done to my standard's
Normally I would agree with you. However, this car is somewhere around 35-40 years old and there is bound to be pitting from all the moisture the brake fluid has sucked up all those years, as evidenced by the piston hanging up on what is likely a rust or corrosion ridge. I virtually guarantee that once the piston is out and you see inside the cylinder walls they will be beyond repair. Brakes are nothing to mess with. They need to work, and work well every time. Price isn't always the consideration, but in this case it is probably going to be cheaper, easier and more properly done by replacing the caliper.