I have a single handle Moen faucet - like all faucets it eventually needs maintenance. It was dripping and spurting every time you used it. I looked at youtube and mostly saw people buying parts and putting them in. Also people, with various degrees of success, were trying to get Moen to send them parts. But what is wrong with the valve? Mine has one of those ceramic insert styles cartridges. No o-rings, or washers, and it is ridiculously expensive. So I took mine down to bits and started cleaning everything with vinegar, soaking parts in hot microwaved vinegar, scrubbing with an old toothbrush. Also put vinegar in the faucet top. No parts had any visible wear. There was limescale on everything - including the threads. I think the original install of the cartridge was just a bit loose (is that a factory oversight? or you have to be pretty smart to be so dumb? ) So after cleaning it all up and putting it back together it works, no drips. I think limescale was just preventing the parts from mating closely together and water was running through the threads and out the top.