S90: Piston Out

Unfortunately, found the S90's cylinder was heavily corroded on the bottom where moisture (I assume) would have collected and sat.

Piston looked to be in great shape, though.

I did snap the oil ring while trying to get it off.  Not sure if that was me being too rough, or if it was just brittle with age.  Perhaps a little bit of both.

Also gave everything a nice scrubbing with the wire brush before reassembly.