Q. "Water is leaking from the top of the stem when the hydrant is on. What can I do to fix this?"
A. The heater well thumb nut (item #11) may need to be tightened. Or, the heater well washer (item #12) may be missing or worn, or the heater well (item #13, #13a, #13b) may have a hole or split in it. To inspect the heater well, unplug the power cord. Unbolt and remove the head covers. Pull the heater and cord assembly straight up and out of the heater well. Remove the thumb nut (item #11), and the handle (item #5). Pull the heater well (item #13, #13a, #13b) straight up and out of the hydrant carefully so as not to bend or dent the heater well. Inspect the heater well for holes or possible splitting. Replace the heater well, or if the heater well looks good, reinstall the heater well. Reinstall the handle and the thumb nut and tighten the thumb nut. Slide the heater back into the heater well. Replace the head covers and bolt into place and plug-in the cord.