drive back on
drive (one) back on (something)
To force one to use some resource, especially one that had been held in reserve. It was a tough time financially, as losing my job drove me back on my savings.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
drive someone back on something
to force someone to tap reserves of something. The hard times drove them back on their life savings. The challenges of being a corporate executive drove her back on all her personal resources.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.