When cleaning out our dishwasher recently I removed the lower spray
arm, which clicked out easily. Since putting the thing back together
though I have noticed that the things in the lower basket do not clean
properly and after removing the lower spray arm once more I can see
that there is a gap going around the connector where I might expect a
rubber seal to go. If this has broken it may explain why the things
in the bottom of the dishwashers are not being cleaned as water may
the escaping and the pressure of the spray may not be enough.

Does anyone know if it is usual for dishwashers to have rubber seals
around the connectors for the spray arms?

Cheers,

Dave.