Theory

• Hydraulics work by pressure being applied on a liquid that is moved to push or pull a piece of machinery. The theory of hydraulics proposed by Pascal determines pressure moves equally through fluids.
  
  

Pistons

• Hydraulic cylinders house the mechanical workings of the hydraulic system, such as the pistons and rods. The piston is moved by the pressure applied by hydraulic fluid, a piston seal stops pressure bypassing the piston to the other end of the cylinder.
  
  

Action

• Hydraulic cylinders can either be single or double acting, depending on the need of the machinery. Double acting hydraulic cylinders have ports at either end allowing pressure to flow either way through the cylinder to push or pull.