I have a 12 yr old Kohler kitchen faucet with separate handles and separate spout. The spout is leaking at the base only when either the hot or cold water is running or not. Do I have to unscrew the nut underneath the spout under the sink or can I remove it from the top? If I'm stuck with removing the nut, what kind of wrench should I use in such a confined space under there? Once I get it out, how do I fix the leak? I don't have the model number.