Abstract: An improved lift mechanism for raising and lowering the tops of pop-up tent campers and similar vehicles. The mechanism of the present invention is used to simultaneously raise or lower a pair of telescoping support posts that connect the extendable top to the body, and includes a pair of guide housings that connect to the telescoping posts. A pair of substantially incompressible flexible springs is slidably disposed within the guide housings, and a drive cable extends between the guide housings and connects the flexible springs so that movement of one of the springs produces a simultaneous movement of the other spring. A block housing having an internal pulley is attached to each end of the guide housings, so that a single drive cable can be used to activate both of the flexible springs at once.