bucket of rust

bolt bucket

A machine, especially an automobile. Implies that the machine is clunky or unreliable.

brain bucket

A protective helmet, as worn, for example, by a motorcyclist, bicyclist, or soldier in combat.

bucket down

To rain heavily.

bucket list

A list of tasks arising during a meeting that are put aside to be dealt with later.

bucket of bolts

A piece of machinery that is not worth more than its scrap value, often an old car.

bucket of syrup

A sticky, difficult situation.

can't carry a tune in a bucket

Sings very badly.

couldn't carry a note in a bucket

Not musically talented, unable to sing.