dcxc The best thing to do is to remove the seat.The seats for this faucet just unscrew from the faucet body.Shut off the water ,remove the stem and shine a lite on the seat to see what condition it is in.An allen wrench will work on some seats.You might have to purchase a universal seat wrench from a hardware store,remove the seat and take it to a plumbing shop for a replacement,do both hot and cold sides as well as replacing both “boots