Long intro, short question... My home was built in the later 1940s and has an American Standard three handle tub/shower in the main bathroom. When we moved in 20 years ago it worked fine but after some years it leaked more and more out the spout while in the shower position. Eventually I had to replace the cartridge, and the only one which I could find that fits is a Lasco S-961-4, which claims to be equivalent to an "American Standard 5184". This is not an exact replacement for the cartridge which was removed. That one retracted almost fully into the barrel, so it took about 3/4 turn to go from shower to tub positions. The Lasco plunger sticks out much further when retracted, so it only rotated about 1/2 turn between positions. It also leaked out the faucet from the get go, but not a huge amount. Eventually the first Lasco wore out (the plunger could move up and down without being rotated) and it was replaced by a second Lasco of the same number. It differs subtly from the first: it only allows 1/4 turn between positions, and the big nut that holds the stem in place was made badly, it is a hair too big for the wrench set (so I reused the old nut which did fit.) As before, in the shower position there is a substantial drip out the spout. That will get worse as the stem ages. In the tub position the rubber washer on the end of the plunger is pushed up against the seat, and it doesn't leak that way (nothing dribbles out of the shower head). In the shower position the plunger is fully retracted and the plunger fit into its barrel seems to be tight. However, the stem doesn't fit all that snugly into its cylinder, so that (I think) water is going around the stem from the sources on each side and draining out the faucet. There is no O ring on the plunger end of the barrel to prevent this, only the one at the handle end to prevent leaks out of the handle.. So, what can be done to make these diverters divert 100% when in the shower position? I tried to find a real American Standard diverter on their site, but finding things there is next to impossible, and I was not successful. Here is a picture of the diverter stem: The first stem, which was in place when we moved in and did not leak at all originally, was not this Lasco. Viewed at that angle you could only see a sliver of the plunger.