Dancing dad sang with cast iron bucket (4,4,3,4)
I believe the answer is:
rain cats and dogs
'bucket' is the definition.
(I've seen this before)
'dancing dad sang with cast iron' is the wordplay.
'dancing' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'dad'+'sang'+'cast'+'iron'='dadsangcastiron'
'dadsangcastiron' with letters rearranged gives 'RAIN CATS AND DOGS'.
(Other definitions for rain cats and dogs that I've seen before include "bucket" , "Pelt" , "To fall heavily" , "come down hard" , "Pour" .)