I have 3 handles in my shower; hot, cold, and diverter. I replaced each of the faucets, but was unable to remove the seat screws in each, although I did try pretty hard. I am now getting mixture or hot and cold water when I turn the faucets on? Could I have damaged the seat screws and would this allow for the water to come out of the faucet mixed when only one of the hanldles is turned on? Thanks.

These old style 3 handle faucets are difficult to work on. Did you use a seat wrench? I'm a little confused by your description though, you said you replaced the faucets. The faucets are the brass valve bodies and all of the parts behind the walls. Do you mean you replaced the gaskets? If you do, then if you damaged the seats, you could be getting some crossover. Crossover, happens when you flush a toilet and the cold water is drawn towards the toilet through the shower valve. When this happens, hot water is drawn down the cold water pipe to the toilet. When you then turn on the cold water pipe, you get warm water. In addition, if the hot side is damaged, when you turn on the cold water it can draw hot water up through the damaged hot side.

Raymond VinZant Plumbing Prof.