Time to put some new lines on the Voyager and thought it would be a great time for a brake system rebuild (Had to break into two parts as there is a post is limited 8 hyperlinks)
Fluid Looks a bit off but I flushed last spring so I think it's just the window that's manky:

Old school single pot slaves:

Brake system hydraulics comes off in one piece:

I used the master cylinder to move the pistons out of their bores as far as I dared (to avoid spilling brake fluid on everything), then disconnected the lines, poured the fluid out the banjo bolt holes, and used this trick to pull the pistons out:

Pistons look good as new after some very light metal polish:

Was prepared to change the slave cylinder piston seals but on close inspection, nothing wrong with the originals so I reused them. I've successfully reused good shape seals many times in the past without any issues:

Seal groves required little to no cleaning - never experienced that before - they're usually full of gray crud - crystallized brake fluid? Also never seen the 'inside' of the caliper painted before - maybe the paint limits formation of the grey crusty stuff? Wonder what paint Kawasaki used that is brake fluid resistant?

Cleaning inside of Master Cylinder fluid window with Q-Tip:
