How much slop are we talking here to believe the o ring is bad? Both my pumps rock a little bit in my hand which is evident watching the pump arms as I’ll call them move in unison. Maybe a 1/16th of an inch of movement. Both are the same.
That sounds like they are bad. Not having any exoerience when I bought mine, I thought it was normal but once you replace it and see what it feels like after it’s night and day difference.