Pilot Valve is the small valve we use to control bigger valves in the hydraulic system. It uses low-pressure oil signals from joysticks to shift spools that then direct high-pressure oil in the main valve. We mount it near controls so the machine reacts quickly when we move a lever. If it leaks or gets dirty, valves respond slow or rubbery. We service it by cleaning filters, replacing seals and making sure oil lines stay tight. Think of it as the mini boss telling the main valve.