1995 Volvo 850 fuel pump

I'm guessing the fuel pump is the issue here. My brothers 1995
850 died on the freeway the other night, started and died where it
coasted to and stopped. Yesterday I bumped the bottom of the fuel tank
and heard something bouncing inside of the tank (like the float was
sitting on the bottom) and the pump energized for a moment and quit. I
did it a couple more times and it did the same thing. Anyhow, assuming
the pump is just dead, I want to replace it. Never worked on Volvos
before, I found the hatch in the trunk for replacement of the pump.
I'm not sure which one of the spin on (they look like they spin on)
tops need to be removed.. there's a smaller one towards the front of
the car with electrical connections in the top of it, and a larger one
behind it with fuel lines attached to it. Which one should I remove or
do I need to remove both locks?

Thanks