Converted to dual master with disc/disc. MC is corvette style without residual. MC is mounted high. Proportioning valve installed in rear line, wide open now until I can adjust. I have a couple hundred miles on new brake assembly. Brakes work great until I drive and things get hot, 15 mins of fun, then brakes start dragging hard. Notice that pedal is not returning fully. After cools down, behaves okay for a bit. Checked clearance on rod between booster and MC, it has proper RCH. Put MC on bench, and while bench bleeding I notice that piston does not retract all the way to the clip. If I plunge all the way, and let go sharply, piston retracts fully. If I plunge all the way, and slowly come out, piston stops with 1/3 travel to go. Found the problem, but sort of weird... why is it happening? It sat for a few years with fluid, bled, functioning brakes. MC was purchased new, not rebuilt. It's the type for hot rods with ports on both sides of MC. Sooo... I figure I need to run a hone in the bore. Clip comes out, and first spring and seals come out. The second piston remains in there. If I plunge on it, I can see that is the one with the bad behavior of retract fully if let go sharply, and stops short of I retract slowly. Questions: - How do I remove it? I can't get any tools deep enough to grab the tit. - Does it sound like a hone will fix the problem? Thx.