Leaky fuel sending unit

'93 XJ 4.0L

My fuel sending unit is leaking.

It is definitely not leaking at the tank flange or O-ring.

I've narrowed the leak to come out either at:

1) the hard plastic "plug" where the wires come through the flange disk.

2) ...or the joint the tubes are brazed onto the flange disk.

I've tried several times to wipe everything dry in order to try to spot the
exact origin of the leak but this has proved very difficult because even the
tiniest amount of leaked fuel seems to instantly seep across and wet the
tubes and plastic plug at the same time.

The locking ring and flange are dry, so it looks as though they're OK.

None of the usual parts sources and self-pick yards seems to have this item.

The local Jeep-Chrysler dealer quoted me $439.00 for a new sending unit.
He didn't mention whether if that included the pump ...but I positively felt
as though it was my wallet that was being "pumped".

I was thinking of maybe using some sort of sealant on both the inside and
outside of the suspected areas of the leak.

Has anybody done this?

Any recommendations for a sealant?

I thought about using J-B Weld, but that stuff can sometimes takes over
24 hours to set.