cracking open brake caliper bleeders?

I would try several applications of Break Free (gun oil) 24 hours before putting a wrench on them. And then use a 6 point socket and put a little effort / pressure in the tighten direction before I tried to loosen them.

I try soaking them with the equiv of penetrating oil for several days before I plan to work on them. (I have an extra car.)

The "trick" is to not push or pull on the wrench, but to bang the wrench with your open palm. The sudden impact usually breaks it free. Its worked for me for several years whenever I need to loosen a brake line or bleeder. Lines and bleeders are made of stainless steel and bind up over the years. The longer the line wrench or ratchet handle the better.

Ever notice that a 130 dollar caliper can be made into junk by a 10 cent bleeder. The best way I have found is to take a small propane torch and heat the area around the bleeder. Make sure to use the exact size of wrench, some are metric and some are SAE. Good luck

I know what you talking about as far as a cheap part like a bleeder break turning a caliper into junk.
Unless you regularly loosen and tighten them, they can easily become frozen and break off.
I've got to believe that a more sure fire way can be developed to bleed brakes.

A shot of PB Blaster should do the trick with the right socket.