anyone know how to stop leaky oil tubes

[Norm Faustino]

I just replaced the oil return tubes on my 78 sc with the expandable green seal type and they all sealed except for one, I even pulled it back out to reset it and no joy! it still leaks overnight (a considerable size puddle) can anyone help with tips and tricks on this one.
thanks
Norm

[Rot 911]

When I put mine in I greased up all the seals with a liberal amount of Dow111 silcon lubricant. No leaks.

Kurt V
72 911E