leaking American Standad tub faucet

I had a leaking american standard tub faucet (721X) and replaced the cartridge as suggested. The tub faucet is still leaking the same amount of hot water- steady trickle. I do not see many posts on this type of faucet cartidge set up and was looking for advice. The set up consists of a plastic round cartridge with 3 holes at the rear that mates to the shower body and when the handle is turned it regulates the flow.

Any input would be greatly appreciated.