If you have just replaced the stem inside of your Mansfield faucet, and there is still a leak from behind the handle. The first thing you would need to confirm is that you are using the correct graphite packing for your faucet. If you thread the plastic packing nut into the faucet by turning it to the right. You would need to use the smaller thick graphite packing. If the packing nut is installed by turning it to the left you would need to use the larger flat packing. If you are using the correct packing, and it is till leaking from behind the handle. It most likely means that the new graphite material packing has not been compressed enough to make a water tight seal. This issue can be resolved by loosening, and re tightening the packing nut. You may have to do this a few times in order to compress the packing into a cone shape, which will then create a water tight seal. Click Here To Go To The Mansfield Faucet Guide