Controlled priority fluid system of a crawler type vehicle

In a fluid system of a work vehicle having a pumping means having at least one pump serving at least two primary work elements and at least one secondary work element, the improvement comprising:

• first means for delivering fluid from the pumping means to the first primary work element for the operation thereof;
• second means for delivering fluid from the pumping means to the second primary work element for the operation thereof;
• a bypass conduit connected to the secondary work element;
• third means for sensing the fluid pressure of the first primary work element, delivering a first signal in response to said sensed pressure and selectively passing fluid from the first means into the bypass conduit in response to said first signal being of a magnitude greater than a first preselected value while maintaining said first primary work element free from communication with said first means;
• and
• fourth means for sensing the fluid pressure of the second primary work element, delivering a second signal in response to said sensed pressure, and selectively passing fluid from the second means into the bypass conduit in response to said second signal being of a magnitude greater than a second preselected value while maintaining said second primary work element free from communication with said first means.