if you snap one there is a kit where you can drill a larger hole and then it has it's own bleeder, of course best not to snap them off but it happens.

what I;d do is use a small 6 point socket, put some pressure on the wrench and at the same time use a small hammer to tap the wrench , the shock and torque ombined can help to not snap them.

I made up a bleeder using a pressure cooker as my reservoir and a vacuum generator. I connect the vacuum generator to the pot and it creates suction and runs off my air compressor. the pressure cooker collects the used fluid that way.

you can look up "vacuum generator" if unfamiliar with them, very simple venturi device, no moving parts. they make an air rushing sound and use a fair amount of air

I prefer to do that than to try to pressurize the system. Just a different approach.