How can I repair my PricePfister tub/shower fixture?

My 3-knob PricePfister tub/shower faucet was dripping through the spout and into the tub when both hot and cold knobs were turned off. I replaced the stems and the seats on the hot and cold water knobs. The fixture still drips (although not as much) through the spout when the knobs are turned off. Other than changing the entire fixture, is there something else that can be done to stop the dripping? Thanks