Before putting the new one in, clean out the
inside of the faucet and apply a little plumbers
grease to the walls of the faucet and on the new
cartridge. then slide it in. Make sure it goes
all the way in.
I received an email today from a visitor that was installing a new cartridge in a Moen kitchen faucet, he said he followed my instructions by adding a little more grease to the cartridge before installing it, as it turned out adding the extra grease was not a good thing, because it caused the faucet to shut off by it's self do to the weight of the faucet handle. The cartridges come pre greased, so if you can get it to slid back in with out adding the extra grease, you should do so especially if you are repairing a kitchen or lav faucet.