Make sure you have BOTH the silicone "nubs" that are pressed in at the bottom of the
tank body where the center pin goes up through the
tank, and there's also another silicone "nub" that presses into the top of the tank where the center pin exits, and the 3 knurled nuts screw onto it to capture the coil wire and hold the center pin to the tank.
Edited for clarity...there should be 2 silicone pieces total, one at the top and one at the bottom of the tank. The center post passes through both. Maybe you knocked one out unintentionally when taking the tank apart for cleaning? They prevent the center post from contacting the tank body and causing a dead short.