The Dictionary of American Slang, Fourth Edition by Barbara Ann Kipfer, PhD. and Robert L. Chapman, Ph.D. Copyright (C) 2007 by HarperCollins Publishers. Cite This Source
Idioms and Phrases with like a ton of bricks
Very heavily, without subtlety. For example, If he doesn't like your work, he'll come down on you like a ton of bricks. This expression, often coupled with come down on (def. 1), replaced the earlier thousand of brick or hundred of brick. The allusion in all these is to the considerable weight of such a load.
[ Early 1900s