bucket of rust vs rattletrap

bucket of rust

noun
  • Synonym of rustbucket 

rattletrap

noun
  • A mechanical device, particularly an automobile, that is worn out, run down, or mechanically unreliable as indicated by noises it makes in operation. 

adj
  • Mechanically unreliable or in disrepair. 

How often have the words bucket of rust and rattletrap occurred in a corpus of books? (source: Google Ngram Viewer )