Review on Pfister 9100320 Cold Faucet Cartridge by Tingate Skrbec

My faucet (formerly Price Pfister Treviso) used cartridges #910-024 and #910-025. These parts have been superseded by the newer part numbers 910-031 and 910-032. The instructions for this new cartridge state that the brass retaining nut from the old cartridge should be reused and the new white plastic retaining cup and red or blue o-ring (both visible in Revain's photo of the cartridge) discarded. HERE I HAD SOME PROBLEMS: The knurled black plastic shaft has the small black o-ring shown in the illustrated instructions. The photo is difficult to make out, but the text is not mentioned. In fact, that o-ring gets stuck in a new white plastic cup that you're supposed to disassemble and discard (at least that was the case with all three cartridges I received). You must remove this o-ring from the white plastic shell and reinstall it on the black rod before installing the new cartridge. If this is not done, the new cartridge will not leak well. Also, when removing old cartridges from a faucet, the bottom of the cartridge can separate from the top and remain in the faucet. It's hard to see because it's black and sitting in a water hole, but it needs to be fished out before installing a new cartridge. I used a metal pick and needle nose pliers to pry it out. This has happened with every valve I've replaced. This may not happen to you, but an old plastic cartridge splits in two very easily, so be aware.