If you close both valves and have no air leaks in your hose, indefinitely. But, never rely just on the jack to keep your car in the air. Always use jack stands. Anything designed to go up and down, can not be trusted not to go down when you don't want it to.
By Elizabeth Bulwer
the Air Jack can hold up the air very long unless the tire is released with the air. There is no need to raise the airbag to its maximum height, just raise it to the required height (such as squeezing off the ground), turn off the ball valve switch to stop the air supply, plug the safety bracket, and then start working
By Regina Bart
