Hi Oscar, Thank you for your question. If your model B2511LF-SSPPU faucet is a newer installation putting a small amount of plumbers grease on the o-ring around the stem assembly should stop the squeak. If the faucet has been used for a longer period of time the stem assembly should be replaced. Please refer to the attached manual to find the correct replacement stem assembly as the faucet has two different part numbers based on the code found on the back of the escutcheon plate. The correct part numbers and where to find the code are on page 3 of the manual.