I have a Moen 7400 faucet with a separate sprayer. It is leaking from the base of the neck where it meets the deck at the split gray o ring. Any ideas on how I can take it apart to replace the o ring? I can't seem to find any allen wrench connections or screw holes.

I have a Moen 7400 faucet with a separate sprayer. It is leaking from the base of the neck where it meets the deck at the split gray o ring. Any ideas on how I can take it apart to replace the o ring? I can't seem to find any allen wrench connections or screw holes.
If I understand the problem your faucet's leaking at the base of the spout, correct?
Remove the handle,( There are three handles on your model. They all have piop-off plates on top and a regular screw under that. And cover. Unscrew the retaining nut and pull the spout up. Replace the "O" rings and grease them lightly with silicon jel. Reassemble and rest. Good luck, Tom

Follow Tom's instructions, and open the PDF file below locate your faucet and it will show you how to remove the handle the spout and the oring or the cartridge, good luck.

John

http://www.moen.com/shared/pdf/7430pt.pdf