Question

pressure will cause the vehicle to fall without warning. this is why you never position your body under a vehicle without first supporting it with jack stands. a hydraulic jack can have external and internal leaks. an external leak means the hydraulic oil is leaking to the outside of the jack. external leaks are easy to identify because hydraulic oil will be found on the out side of the jack. the major cause of external leaks is worn piston o - ring and/or worn piston. internal leaking means the hydraulic oil leaks inside the jack, from the pressure chamber to another low pressure area. this type of leak is evident by the self - dropping of the weight supported. this is often caused by a leaking release valve. identifying a leaking hydraulic jack - observe the outside of the jack for signs of relative fresh (moist) oil. the most common leak points are the piston o - ring, the release valve and the pumping valve. you can identity the severity of the leak by observing how much oil is on and underneath the jack. an excessive quantity and fresh oil on and underneath the jack where it is stored means there is severe leak and the jack should be removed from service. a small amount of old, dry accumulated oil near the piston however is considered normal, since the o - rings cannot completely prevent oil from going to the outside of the jack. - to test for internal leakage, you can try to jack up some load with the jack in question. wait for 20 minutes, observing how much height the jack has lost. for a normal functioning jack, the height drop should be almost imperceptible. if the jack drops significantly and there is no obvious leaks on the outside then it is most like caused by a leaking release valve. important: the load youre jacking during this test should be stable; with a back - up support in place, to prevent the load from falling, should the jack suddenly fail. what could happen if a leaking jack is used to lift a vehicle? the jack could drop, cause injury to the person when lifting the vehicle or when positioning safety stands.

Explanation:

The text states that a leaking hydraulic jack can have internal or external leaks. Internal leaks can cause the weight supported to self - drop due to a leaking release valve, and external leaks are from worn piston O - rings or pistons. Using a leaking jack to lift a vehicle is dangerous as the jack could drop, which can cause injury to the person lifting the vehicle or when positioning safety stands.

Answer:

The jack could drop, cause injury to the person when lifting the vehicle or when positioning safety stands.