Quote:

why do my Milodon pumps ALWAYS prime themselves?



They'll prime themselves alright ... how LONG it takes to prime is the issue! The engine should have pressure almost instantly when it fires. If the pump takes a couple seconds to prime and build pressure then there's potential for wear in the motor.

So you solved "your" problem by sealing a leak. Great! But that's not the most common cause for loosing the prime.