I've taken off the sintered filter on the body of the pump and that seems OK.
I've taken off the 'trombone' tubes from the body of the pump and there's not much to see except a slightly shaved O-ring at the base of the nut which holds the tubes to the body. This shouldn't matter unless the shavings have gone into the tubes.
There were a couple of drops of water in the cavity at the base of the body of the pump.
What next please?