Turn off the water supply to the bathtub
Open the faucet handles to drain any remaining water
Plug the drain to prevent small parts from falling in
Remove the handle caps if present
Unscrew the handle screws
Pull off both faucet handles
Remove the escutcheon plates or trim covers
Unscrew and remove the valve stems or cartridges
Inspect the valve body and clean the area
Apply plumber’s tape to threaded connections if needed
Install the new valve stems or cartridges
Reinstall the escutcheon plates or trim covers
Reattach the faucet handles
Tighten all screws securely
Turn the water supply back on
Test both handles for leaks and proper operation
Caulk around trim if needed