i can't zoom in to do that

Zoom in on the water level gauge and you'll see a "hot spot" just behind the wheel you just placed. Something's missing! Use your screwdriver to hold the wheel in place

Move forward and examine the gold bars. When you're finished you have to leave the room and tell somebody! Turn and start heading up the ladder.

Use your screwdriver to hold the wheel in place. Zoom out and zoom in on the left-most wheel. Turn that wheel. Turn to the right again, and turn the newly placed wheel. Now turn the right-most wheel. Watch the water level gauge go up. The well is now full. Take out the screwdriver, and put the wheel back in your inventory. Zoom out and turn left. You should now be facing the well door. SAVE YOUR GAME HERE. Turn the center wheel and then turn the left handle. Enter the well. Go down the well and turn around.