blue dot caliper issue

[fjfool]

looking for your opinion on this issue
i rebuilt my blue dot calipers with an aftermarket seal kit that came outa the UK, as the oem part is not available from Yam anymore
i noticed that the smaller pistons seemed especially loose after installed
after riding for a couple hundred miles i was experiencing some pad drag
bled and rebled, cleaned, to no success
removed the pads and pushed the pistons out and this is what i saw:

[fjfool]

looks like water contamination to me
what do you guys see?
i was able to ebay some OEM seal kits and have installed them, i will see what they look like in a month for comparison

i feel the white ring of crud shown in the pic was keeping the piston from being retracted by the seal and causing the drag
your input is appreciated

[FJmonkey]

It does look like scale from water deposits.

[ribbert]

How did you determine the they were dragging?

As you know, the seals don't slide when the brakes are applied.

Noel

[Bones]

Did you smear the seals and pistons with brake fluid before installing, they look dry to me.