bathtub faucet leaking in the wall

I have a 1960's bathtub compression faucet with separate handles for hot and cold. I bought Sterling replacement parts and replaced the seat and washer, stem and washers on it, -everything except the bonnet. When I turn the faucet on water leaks out in the wall where the stem is screwed in. I have no clue what to do next. Please help!

If it was the 60s there is probably a packing gland as opposed to o-ring stem seal. If it's a gland there will be a six sided nut to remove from the assembly and you should add some string teflon packing. that should tighten up your leak.

If you installed a new valve stem, they usually come with the packing nut loose. You may have to remove the stem to tighten it, using a wrench and a counter-wrench. The packing material should already be in there.

Arrow in photo shows packing nut.