On my pump with the hex nut on the drive shaft hand tightened my wet side metal disk cannot touch the gasket. It's near impossible. It spins freely but is entirely contained within the frame. I've taken my pumps off a few times and when I look at the orange wet gasket it has almost no wear marks.
So does your wet side metal disk, when the nut is tightened, extend to the end of the wet frame or even slightly out? If so that sounds like the difference.
So does your wet side metal disk, when the nut is tightened, extend to the end of the wet frame or even slightly out? If so that sounds like the difference.