Well ... I've fixed one problem to create another. My dishwasher seal started to leak and I repaired it using the kit

Everything works fine, except that now the lower spray arm does not spin. It spins freely when I installed it . But during washing it becomes binded by , I asume, seal rings. I've put apart and back the whole pump several times - the same story: after the installation the lower spray arm spins freely, but gets stuck right after water begis to flow. As if the seal rings are pushed up and prevent it from spinning.

Any advice is greatly appreciated.