I have a 20+ yr old Gerber 3 handle tub faucet setup; hot and cold knobs and a diverter knob in the middle. The hot/cold stems were leaking so I replaced everything; both stems with new valve seats,washers, etc. and a new diverter with a new seat/washer. The stems no longer leak but now I have water dripping from the tub faucet. I crank down on the hot/cold knobs but it still drips, although slower. I took everything apart and checked all the flat washers and the tightness of the seats. All were as they should be. I even went ahead and replaced all the flat washers. I put it all back together and the faucet still drips.
What more can I do? Any ideas??