Retainer for 1.05" distributor orings 5600, 6600, 6700, 5000, and 2510
PN 13030

For some reason this part is not shown in most of the Fleck Diagrams.
It is simply "pressed" into the center opening for the distributor.
The o-ring ( 13304 ) sits just immediately above the retainer.
The retainer is what keeps the o-ring in place.
So, you just need to take the retainer, and force it into the center opening of the valve body at the bottom.