My front brake had begun binding so, based on previous experience I decided to clean the pistons and fit new seals.
The whiteish deposits in the photo seemed o be the source of the problem. I removed them with brake cleaner and
a tooth brush.
Nb you will need a hard tootbrush.(the medium one in the photo proved ineffectual). Also took the opportunity
to grease the sliders with WD40 Silicone Lube.
Suxzuki Part No. for the seals is 59300-13820.