Bathtub faucets come either as two-handled compression faucets, or as one-handled washerless faucets. Washerless faucets themselves come in three types: cartridge, disc, and ball faucets.
Worn rubber washers, seals or gaskets in the valve assembly cause most leaks. In this article, we’ll show you how to fix a stem-type valve, which is common in older, two-handle faucets (separate hot and cold).
You repair a two-handled shower valve just as you would a compression or cartridge faucet in a sink (see How to Fix a Faucet), except that you might need a deep socket wrench to remove a valve stem that's recessed in the wall.