Hpop reservoir leakdown

[JJR]

Hpop reservoir is leaking down overnight. What are the most common ways this can happen? Looks like the only way it can is through the hpop. Truck starts right up then dies and then cranks till reservoir refills then starts and runs great. It just is really annoying. I have allready replaced the lpop with the Melling unit which helped it fill reservoir faster but it still drains down. Any ideas on where my oil leaks down through?

[steve604]

i'm having a similar problem and came accross this thread
rebuilt 7.3 not starting no oil pressure HPOP not staying filled

it looks like "GAS" has the right idea with checking out the ball and spring behind the allen bolt