Delta 2600 & 2800 Three handle bathtub faucet leaking

[losten]

Hello, all. I could desperately use some help trying to fix a bathtub faucet leak. Water has been leaking from the faucet since before I bought the house (about a month ago) and has been recently getting worse. I have a three handle setup in a home built in the late 1960’s. I know next to nothing about plumbing and my initial research led me to believe the leak was likely due to a worn washer that needed to be replaced.
I was finally able to get the water turned off and one of the handles removed and...it wasn’t what I expected. I’ve attached pictures of the hot faucet handle I took off and the back access view of the brass piping. I can’t see any discernible connection point for the stem/how to remove it and now I’m starting to wonder if an old washer is even the problem.
I’m a little in over my head at this point and haven’t been able to get any professional help out here because COVID is hitting my area hard at the moment. Any help figuring out what the likely culprit is (and how to fix it) would be very much appreciated.

 

[Marlinman]

If the problem is not turning off completely or leaking at the stems the RP4993 seats and springs and RP1740 cartridges will take care of the problem. Be certain to use plumbers grease or silicone grease on the seats. See the link

https://media.deltafaucet.com/PartsDiagram/2653_2683_2861_2871__32922_Rev_C.pdf

 

[Sponsor]

 

[losten]

If the problem is not turning off completely or leaking at the stems the RP4993 seats and springs and RP1740 cartridges will take care of the problem. Be certain to use plumbers grease or silicone grease on the seats. See the link

https://media.deltafaucet.com/PartsDiagram/2653_2683_2861_2871__32922_Rev_C.pdf

Thank you so much for this! I was able to replace the stems, seats, and springs on both the hot and cold. That stopped the leak for about three days but now it’s started to slow drip again so I don’t know what the problem could be, unless I made a rookie mistake trying to fix it. I think it might be time to wait for a plumber.