This damned 11mm Brembo brake cylinder…..
It seized up again. This time, I knew what was happening, so I was able to address it before it totally went nuts. I was able to recover the white sleeve and do the repair to the main bore without burning through one of my precious and rare rebuild kits.
The critical element is a PTFE sleeve that is 18mm long, 2.5mm wall thickness, 16mm outer diameter, and 11mm inner bore.
Given an endless supply of white sleeves, one could conceivably simply continue to clean out the poorly-designed master cylinder bore quite a few times before it was completely beyond salvage.