Below is a list of Hydraulic Directional Control Valves manufacturers from Vernon Hills, Illinois. Hydraulic directional control valves are parts that are designed to control the flow and direction of a fluid in a hydraulic system in order to prevent improper levels of pressure. They perform multiple services and can be customized to fit the application. Hydraulic valves are composed of the main casing, the bonnet that is a removable casing section, a seat or connection and a sealing disc.