leak at inlet of water pump

[partsman01]

1989 prowler lynx 18.5 fifth wheel
I noticed on this used unit I bought that the connection that threads onto the inlet of the water pump is leaking, I tried tightening it up, but no help.
I can tell the pump is new, the old pump was left as a spare, anyway, I can see someone tried to use teflon tape to seal it, but I think I will have to use liquid pipe sealer.
And the other thing is, I reconnected my lines to the hot water tank as I drained the system and now the RV dealer tells me the rubber seal in it is no longer available.
But if the picture works, I found in a catlogue bottom right corner #25719, it seems to be what I have and would appear to be available.
Does anyone know if these seals are what are used to seal the line that screws onto the pipe nipples on the 6 Gal Atwood water heater

[partsman01]

1989 prowler lynx 18.5 fifth wheel
I noticed on this used unit I bought that the connection that threads onto the inlet of the water pump is leaking, I tried tightening it up, but no help.
I can tell the pump is new, the old pump was left as a spare, anyway, I can see someone tried to use teflon tape to seal it, but I think I will have to use liquid pipe sealer.
And the other thing is, I reconnected my lines to the hot water tank as I drained the system and now the RV dealer tells me the rubber seal in it is no longer available.
But if the picture works, I found in a catlogue bottom right corner #25719, it seems to be what I have and would appear to be available.
Does anyone know if these seals are what are used to seal the line that screws onto the pipe nipples on the 6 Gal Atwood water heater

[partsman01]

this should be a picture of the rubber seal.