I purchased a pureline 1500 3/4 hp pump to replace the pump that came with my SandPro 75D filter. I unboxed it and noticed that the strainer basket assembly is not solidly attached. The "clamp" is in place, but it still wobbles. I know it is an o-ringed fitting but I can't get the air completely out . I've rechecked the other fittings and they seem solid. I would appreciate any help you can offer.

Thanks in advance,