Plumber 2000 or anyone: My sister wants me to replace the 25 year old Delta single lever faucet on her kitchen sink, and I haven't done this before. I looked under the sink, and noted that the steel bolt, horseshoe shaped flange and nut holding it on are all rusty. It's close to the sink, so there's not a lot of working space to use a wrench, and I'm inclined to try a deep 1/2 inch socket to take that nut off. The rust all over everthing is a bad omen, and I'm wondering what kind of a fight I'm in for. If that nut seizes up and I can't get it off, what else can I do other than cut through the faucet body above the counter top? Also, I'm planning to install a Moen simply because it's easier to replace the cartridge on a Moen than it is to replace the rubbers on a Delta. What are your thoughts on that?

I have copper tubing from fridge to valve. I have tightened nut but water still leaks around nut and valve connection. Should I just buy a new nut or should I buy a tube cutting tool, cut the line off a little and install the new nut? Should I replace the valve also? Thanks, emsandsas