How to top up the oil in the cylinder? During shiping, the jack was turned upside down and some oil spilled. Therefore the second section of the piston refuses to slide out under load.
Open the valve in the picture, put the tank oil in, then squeeze the oil bag, squeeze out the air, and then tighten the valve back. The picture is shown in the link: https://d2v0huudrf11kh.cloudfront.net/vevor-center-goods/7_1664275182650.jpg
