If your American Standard gooseneck faucet is leaking, it's a problem you shouldn't put off, because leaks waste water -- driving up your energy bill -- and they can discolor the sink. It's possible for these types of faucets to leak from the base of the spout or the handle, but most of the time, the leak is coming from the spout itself. That's normal for an old faucet -- it means that a rubber part has worn out. You don't need a plumber for this repair; it's surprisingly easy to do yourself.
Leaks from the Base of the Spout
Turn off the shutoff valves under the sink, and open the faucet to allow water to drain.
Remove the spout if water is leaking from the base. To do this, wrap a rag around the collar at the base; grip the collar with adjustable pliers and turn it counterclockwise. When the collar is loose, unscrew and remove it, and then pull off the spout.
Look for O-rings around the base of the spout or the stem of the faucet housing. Pry them off with a flat-head screwdriver and replace them with new ones. You may have to take them to the hardware store to make sure you buy identical replacements.
Lubricate the new O-rings with plumber's grease and slide them into place. Replace the spout, and screw on the collar.
Leaks from the Handle or Spout Tip
Turn off the water and unscrew the faucet handle. If yours is a single-handled American Standard model, look for a hex screw under the lever and unscrew it with a hex wrench. If your model has two handles, unscrew each handle with a Phillips screwdriver. Remove the handle and, if there is one, the decorative collar underneath.
Release the valve. Most American Standard single-handle faucets have a disk valve that you release by unscrewing three Phillips screws. Two-handled models have modified compression valves that you unscrew from the valve housing with adjustable pliers.
Replace the rubber seals in the water inlets if yours is a single-handle faucet. Pry out the old ones with a screwdriver and push in identical ones. If your faucet doesn't have seals, and you suspect the valve is faulty, replace it with a new one. You can't fix broken disk valves.
Unscrew the screw holding the rubber washer to the end of a valve in a two-handle faucet. Replace the washer with a new one.
Reassemble the faucet after replacing the worn parts.