Almost all valves have a very high tolerance for metal which is inside of each valve, yes! It is a metal on metal fastening. Especially with directional valves, you can move its handle and make it go in different directions. All this action in regular and frequent use will eventually make the hydraulic valves worn out. Due to the high tolerance of the metal, it may take some time but eventually it wears out only from excess use. Visit http://www.tridenthydraulics.co.uk/ to order your needed hydraulic valves now.