Screw Jack Vs Hydraulic Jack We have some railroad jacks for when we used to move houses, but i wanted to get some new jacks to level beams, etc. I am familiar with the old hydraulic lifts, pump action type. My problem is that i have seen a lot of screw jacks recently. What do you guys prefer? I have hydraulic, I assume they are originals (they tend to look it). No idea if they needed any maintenance before but the previous owner didn't mention it. They work decent but are definitely heave as mentioned maybe 40#? I'd just get them though unless you find some mechanical ones, I don't run with them on anyways. Hydraulic Jack involves a set of two pistons, one small and another large, work is done on the small cylinder (pushing) and this force is transmitted to the larger one via hydraulic fluid, where mechanical advantage is gained and the output piston produces a great force. Hydraulic jacks use this principle, but instead of direct contact between the pistons, the small piston pumps oil into the chamber of the bigger one via a system of valves. In the floor jack, the piston pushes a crank which connects to a lift pad, which is then lifted. Floor jacks have large lifting capacities compared to screw jacks; up to 10 tons or more and also have a higher max lift height.