sink leak

We have a Moen single handle faucet that keep dripping as well as in leaking out the base of the faucet. I tried replacing the cartridge with a new 1225 cartridge, however when I put the handle back on and raise it, it falls back down to the closed position. Then if I put the old cartridge back...

I have a double basin stainless steel sink that was installed in the late 1980s. The left basin has a garbage disposal. Right basin has a standard drain. I was standing near the sink after washing some things in the sink (water going to both basins) when I heard a dripping sound. I looked under...