I rebuilt a set of JDM calipers using the better condition pistons that came out of the original ADM calipers. Measured both with micrometer and as far as I could tell they were the same size.

I fitted a PBR seal kit from the local brake shop to the JDM calipers using the ADM pistons and now I find brake fluid weeping from the seal area. Brakes work fine but there's a definite weep of fluid.

Should I have used a genuine kit? Some other seal kit?

Can the ADM pistons be used in the JDM calipers?