Medi-Dart valve seat (MDVS)

Details

Air leaks are the most common complaint with any pressurised injector, and on a Medi-Dart the search usually ends in one of two places: the o-ring, or the valve seat. The seat is the sealing face inside the syringe head, and it is listed by Medi-Dart among the parts that make up a complete extension syringe alongside the needle, valve cap, nuts, plunger, barrel, tail section and o-ring. Seats wear gradually, so the failure creeps up on you. The syringe that used to hold overnight now needs topping up before you leave, then it needs topping up at the gate, then one day the barrel does not empty properly on an animal you have already walked up to. Replacing the seat is a great deal cheaper than losing that opportunity twice. When you have the syringe apart it is worth doing the o-ring at the same time, since both are in the same air path and both are cheap. A light film of castor oil on reassembly is what Medi-Dart recommends and it helps everything seal in cold weather. Check which syringe you are working on before ordering, as the crossbow dart and the extension pole syringe do not share every part. The seat is a reusable component that eventually needs replacing rather than a consumable you change every time. Treatment choices remain a conversation for your veterinarian and the label.