Originally Posted by husafreak

Time to overhaul the air system on one of my main gears and I have questions... This is the stock CARF supplied sport gear for the Hawk. A leak has developed suddenly and is a cosistent leak starting after about 175 flights. It is coming from the small O-ring that acts as a seal for the piston shaft as the piston moves back and forth in the cylinder. It is leaking when the main gear is up and the air pressure is held between the piston ring seal and the O-ring in the block that the cylinder threads on to. I can hear air leaking and see bubbles forming at this seal. I guess a small piece of debris may have cut or scored that O-ring. My CARF rep here in the states is sending me a new piston but after removing and cleaning and replacing the O-ring and having it continue to leak, and inspecting the piston shaft and finding no defects, I think I need a new O-ring. It is quite small. Does anyone have experience with this or specs for the tiny O-ring? I will also contact the manufacturer of the gear but thought I would ask here first and hopefully source the O-rings quickly and or locally. Thanks