Need some help with a Master Cylinder problem

[silvertj]

I am doing a rear disc, master cylinder and prop. valve swap. I started to bench bleed the MC. All was seeming to go well until I noticed brake fluid seeping out from under the piston. It doesn't seem to be a lot. But it also isn't getting any harder to press in the piston. I have two bleeder valves, with hoses, running into the top of the MC. I haven't gotten any more air out of them for awhile. Does this mean that the MC has a leaking seal? That would mean that this brand new MC is bad? Its out of a Dodge 3500 if that makes any difference?

Thanks