Respuesta :
Answer:
A hydraulic jack uses a liquid, which is incompressible, that is forced into a cylinder by a pump plunger. ... When the plunger moves forward, it pushes the oil through a discharge check valve into the cylinder. The suction valve ball is within the chamber and opens with each draw of the plunger
Explanation:
You can keep the jack under there to be on the safe side, but make sure it's not unbalancing the car in any way, or fighting against the stands. ... If while working under the car you remove the wheels, it's never a bad idea to put them under the car as an extra safety measure.