AMEN to Kroil! I was patient and let it soak in for 5 mins of each application - for 3 squirts - and it broke loose. Right side rubber line / hard line junction broke loose. Two new calipers on the bench.

Back chamber of master cylinder drained out before I broke loose the right side line - so my rubber stopper on the left obviously failed.

With rear chamber drained - it looks nasty in the bottom. Rustish, muckish, nastyish.

Off to parts store in the AM for a new master cylinder and two new rubber lines.

Thanks to those stopping in and thanks to those commenting! Support is great when in these predicaments!