After thinking about those seized wheel cylinders awhile, I realized I was on the right track with the grease zerk plan, but trying to implement it wrong. I was thinking I could install the zerk direct into the cylinder where the banjo bolt goes, but it's that odd M11 size.
Instead I used an sae banjo and put an sae zerk in it. Worked great!
Cleaned up pretty well. Didn't require as much grease as I had feared.
I have new oem pistons, cups, springs and boots for these.
Edit: front are marked ASCO, rear are ALCO. I've seen some others online marked Aisin. All with the teq logo. Wonder what the story is?
I'm off to SC later this week so hopefully the new shoes arrive while I'm gone and I can get it reassembled when I return.