Is the fuel pressure check valve inside the pump, or part of the bucket?

I know there is a little rubber diaphragm in the bottom of the bucket, which is a check valve of sorts. I think it only serves to keep the bucket full when the tank is low. Is there another check valve inside the pump itself?

Fuel pressure bleeds down fast with pump off, and I know the bottom fitting of the new pump was not a perfect fit to the bucket when I recently installed it, so if the valve in the bucket is the one responsible for holding fuel pressure that may be my problem. But if there is a valve inside the pump, too, I'll look elsewhere first.

Thanks.

in the top of the pump, its like a one way valve