I have a 4-year old American Standard single handle shower faucet (shower-only) that would not allow control of the hot water. I replaced the pressure-valve (m952100-0070) which fixed the hot water problem; however, I now have a very small drip from the shower head. I then replaced both the cartridge (m954440-0070) and the shower head, but the drip remains. I have tried to reseat the pressure-valve/cartridge multiple times and flushed out the control unit, but it still drips. Help!