You need a flat blade screwdriver with a notch cut out in the center to clear the retaining pin in the valve. I have used the large flat blade from the hex drive "security" sets that you can buy at the likes of Harbor Freight, they have a notch already in them. Plus if you use the magnet extension you can slip a piece of 3/8" ID plastic tube over the magnetic sleeve, and about three layers of insulation tape and it will keep the screwdriver perfectly centered in the pump tube.