Abstract: Whenever a tractor vehicle of the cab-over-engine type is being parked in a wheels-turned condition, the steering column pitman-arm typically resides in temporary horizontal registry with a foot-hold opening of the tractor frontal bumper. For such environment, an anti-theft device comprises three main components including: a J-hook extendable through the foot-hold opening and engageable with the pitman-arm; a vertical abutment-plate surrounding the J-hook longer leg and abutting the bumper while obscuring the foot-hold opening; and a padlock having its shackle passing through the J-hook longer leg frontally of the abutment-plate. These three main components, and including steadying means for the combination, result in the J-hook being drawn tightly forwardly against the pitman-arm toward the bumper whereby attempted thievery is frustrated because the steering is thereby inoperative.