I have a Delta 1400 series bathtub faucet and it has a drip leak inside the handle where you turn the water.?

Does the valve cartridge need replaced or just the springs and washers inside the valve cartridge? It only drips inside the water valve handle if you turn it all the way to the hot water side and apply a little pressure to it. The dripping of water comes out right behind the between the plastic handle and faucet valve cover.