Hi, thanks for the addition. Question: I changed the rubber washer of an old shower faucet and there's still a slow drip leak. I checked the seats and cleaned them and noticed that there's a slit in the hot side seat. It looked too neat to be a crack, and also the slit is on the outside of the seat (where the seat rests) so it looks like it's an alignment slit. So that's the question, am I missing a piece on this old hot shower faucet seat? I am this because the hot side goes in further than the right side, where there's no slit. I'm wondering if that slit makes any sense and what kind of piece I'm missing. I'm think maybe a hard plastic with a slit so it rests on the seat? Anyone seen this? By the way it's a "Galt or Galt master" faucet from the 60s. Thanks!