how to repair a moen faucet?

Depends on what is wrong with it. If it is leaking underneath you may want to check your connection line to the faucet. If it is leaking up top you may want to make sure that your handle is connected tight enough. If it is leaking from inside the faucet then you may need to take it appart and replace a simple washer. There are so many Moen single handled faucets (and other faucets) that I would recommend going to a hardware store (or other home improvement store) for a simple $12.95 plumbing book. It will go over faucets (all types) as well as other plumbing needs and it is well worth the 13 bucks. Best of luck to you.  more