Pop Up Pump Not Priming

[pps]

I have 2 challenger 1.5 hp pumps. One is for the skimmer and goes into the filter then returns to the pool, the 2nd pump is for the pop-up system. I don't have a jandy vavle for the pop up pump and I can not get the pop up pump to prime. I replaced the Paramount gear box and it still will not work. There is an intake to the front of the pump that comes up from under ground, then the return from the top of the pump goes back under gound, which I believe goes into the bottom of the pop up control. When I try to prime the pump by filling it with water it only fills about half way. The pupm is not leaking, the impeller is not clogged? It appears that no water is being sucked into the pupm from the intake. Any help please???

[Pool Clown]

Make sure the oring on the pump lid is there, and sealing properly. There is enough water in the pool, right? Level should be half way up the skimmer opening Or, in the center of the tile.

[pps]

Yeah the pool level is up where it should be and the o-ring appears to be in good condition on the pump lid, I even lubed it up with majic lube but still no prime. I think there might be a leak underground where the suction line comes into the pump. Maybe I should have a leak detection company check it out. Thanks for the advice.