Lifting the racing jack handle draws oil from the two oil reservoirs.
A down stroke of the handle pushes pressurised oil to an inner fluid chamber of the hydraulic cylinder.
The two sequence valves located within the hydraulic system each open at different times to enable the hydraulic oil flowing from the inner fluid chamber to the oil reservoirs.
The first sequence valve is opened, while the second keeps pumping the hydraulic oil to the inner fluid chamber to raise the lifting arm.