Hi everyone, I'm in need of some advice. My 50 year old, two handle faucet in my shower will run hot water for a few minutes and then go lukewarm. It happens with only the hot water is on and the cold is off. I have plenty of hot water at every other faucet in the house, including the bathroom sink which is about 4 feet away so I'm sure it's not the hot water tank. We can take long hot showers in our other bathroom with losing temperature. I recently replaced both the hot and cold stems but this only has seemed to accelerate the time at which I lose temperature. Anyone have any thoughts?