A hydraulic lift is a complicated mechanism that requires some work and know-how to build. However, the amount of time it will save you and the amount of work it can produce when finished is well-worth the effort. If you have some mechanical knowledge and the right equipment, it is a project that can be assembled in a few afternoons.
Install the lifting arm or hydraulic cylinder onto a brace mechanism. This mechanism must be strong enough to handle the pressure of whatever it is you will be lifting. Make one from a 1/2-inch steel or iron plate, and drill out the holes to attach and mount the hydraulic lift by sizing them to the hardware. A carbide bit drill or high-speed metal drill is required for this task.
Mount the hydraulic arm to the base plate using weight-tested bolts. This will be your weakest link in the assembly, so use high-quality steel bolts that can withstand the force and stress your lift will produce.
Attach the hydraulic hoses to the cylinder arm. It should be closed, the piston recessed into the arm, while you attach hoses to the two connections on either side of the arm. If your cylinder has an installation manual, follow it precisely.
Install the pump motor and pump reservoir by hooking them up to the hydraulic hoses. These attach on both ends of the hydraulic pump motor. Be sure the hoses are connected tightly.
Wire the motor to a power source. Many pump motors can run from a car battery. If you have another power source, connect it following their instructions. Wire the motor to the negative terminal to ground the wiring. Then connect the red wire, or power wire, and green wires from the motor to the switch. Connect the battery red wire or positive to the switch. Follow your switch wiring diagrams. In general terms, you are creating a simple circuit with the switch.
Mount the motor to your car or tractor, or other assembly for which you are using the lift. This will vary depending on the kind of lift you are building, but for all purposes, the motor just needs to be out of the way of the lift. It can be bolted to a lift bar or mounted on a simple wood box.