Where should i cut a lach opening to get to the fuel pump

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What to change fuel pump but cant drop tank so I want to cut a latch to get to it easily but dont know exactly where to cut and if I need to remove the back set that folds down to a bed got the van caught in high water and I have empty all fluids changed all plugs and wires distribulater starter alternator transmission filter and fluid emitted the gas and replaced with new turned it got good compression blew water all over the inside with caught me of guard and wet syphind out the MFI still won't start trysts but sounds dry. Leave the pump but cant get to it. Why I want to cut a latch to get to it . Thank you. Sincerely virgin machinic!