Distributor o-ring keeps coming off

[JoeyR]

My Kenmore water softener stopped softening our water. I figured out that the problem is that the distributor o-ring keeps coming off, but I can’t figure out WHY it keeps coming off. I don’t see damage or wear on any of the parts that it comes into contact with, but I replaced the o-ring just to be safe and the new one cones off too. Any ideas on possible root causes? Thx in advance!

 

[Bannerman]

It may help to clarify if you attach some photos or tell us your unit's model number and age so we may refer to a service diagram. What you are calling a distributor may be entirely different than what we know as a distributor.