Plumbing in the Home/Faucet
I have a Delta/Peerless single handle kitchen faucet (model P8550) with a single handle, and the rubber seats keep wearing out quickly. Normally it's just the hot side that I have to replace, but the last time it started dripping, I just shut it off at the valve, and now the cold side is dripping as well. It starts off as a slight drip, then progresses into a constant leak. The hot side last roughly 1-2 months before it begin to leak, and I usually don't have issues with the cold side. I have replaced the cold side before, just because I was in there, but I haven't had any issues out of it until now. No other faucet in the house does this. What could be causing this issue? The seat seems slightly compressed and hard I've also replaced the ball, just in case.
Darryl, My fist thought would be the ball but you have changed it. I am assuming you replaced the springs and reset the ball tension on the bonnet as well....I have had luck replacing the plastic ball with a better stainless one but not always.
Make sure you are using Delta parts and that the seats are rather soft and pliable. If it has straight coil springs use the same, if they are cone shaped, use those.
Not knowing how old the faucet is I would venture to say it may be time to replace it.
One last thing, if the faucet was purchased at a big box store, Lowes or the Depot, I have found that they are not the same quality and materials as those purchased at a plumbing supply house. I did not believe this to be the case until a multitude of service calls and faucet failures convinced me that they are not the same. It was proven in my own home when my wife got tired of asking me to replace the kitchen faucet and she finally bought one at the Depot. It lasted less than two years!