Definition of a Hydraulic Jack

A hydraulic jack is a device that uses a hydraulic press to lift, pull or exert pressure.



A typical hydraulic jack consists of a main cylinder, pumping cylinder, check valve, hydraulic fluid, plunger pump, piston reservoir and release valve.

Hydraulic Press Mechanism

In a hydraulic press mechanism, a plunger pump is pulled upward, and hydraulic fluid is pulled out of the reservoir surrounding the main cylinder. When the plunger pump is pushed down, the fluid is pushed back into the main cylinder, while the check valve prevents fluid from reversing into the pumping cylinder. Fluid pressure continually builds in the main cylinder, forcing the piston upward. This pressure on the piston is transferred to the object on which the hydraulic jack is acting.


Hydraulic jacks are commonly used in a range of home, manufacturing, maintenance and technological applications. Most notably, hydraulic jacks are used to lift heavy objects, such as cars or machinery, to access hard-to-reach places for construction or repair work.


Consumer hydraulic jacks are manufactured by several companies, including Craftsman, Blackhawk, Global Industrial, Jet, Mountain, Omega, Simplex and others.


Prices for hydraulic jacks vary based on brand, size and application. Hydraulic car jacks intended for occasional home use range from under $20 to over $200 through online retailers.