How do you fix a leaking tub faucet?

To repair a leaking tub faucet, disassemble the faucet assembly and replace any worn or damaged washers, seals or gaskets. Worn washers, seals and gaskets are the culprit for many leaks, although not all.

To replace the seals on a stem-type valve with a separate handle for hot and cold:

1. Purchase new parts
Purchase the new washers, seals and gaskets for the valve assembly. If the valve is already corroded, consider purchasing a whole new valve assembly.
2. Turn off the water
Ensure the water is turned off at the main valve before beginning work on the faucet assembly. Turn on the faucet to drain any water left in the pipes.
3. Remove the faucet assembly
Pull off the handle assembly. Every handle type is different, but most are screwed on. Some screws are covered, so pry off the cap first to reveal the screws. Then carefully remove the handles from the stem assembly. Do not force handles that are stuck, as the assembly might break. For stubborn handles, utilize a handle puller to complete the task. Once the handles are removed, remove the escutcheon plate and stem assembly.
4. Replace the stem assembly parts
Potential replacement parts include the seat, seat washer screw, seat washer, packing washer and bonnet washer. Replace the necessary parts and lubricate with plumber's grease before assembly. Then reassemble the stem valve and faucet assembly.