My fuel system has lost its prime, I started to use the manual pump and noticed that fuel is leaking from ether the manual or lift pump. has any one had this problem before.

 

I would clime under there and get a real good look,most of my lines were weeping and I had a real mess that is until I decided to do all of them over...

 

I actually have the same problem that you have. The advice given to me was that the lift pump (where you are pumping) has an o ring that gets bad and will allow the leak. The O ring is replaceable, but according to the posts I read easier to replace off the truck, so most replace the whole lift pump (about $150) and keep the other pump as a backup.

If I loosen the bolt on top of the fuel filter, mine doesn't leak. I guess the pressure will build up and get past the o-ring if you don't give the air someplace to go.

 

on mine it was the little elbow-tube between the prefilter/heater and the lp.