Large Brown Fuel Cap "O" Ring

The O-rings and stem seals around the fuel caps and cap center shafts don't last forever. When they wear, water may leak in with nasty results. Two styles of O-rings have been supplied in RV kits. They are not interchangeable. They are easily identified by color: older O-rings are black, newer ones are brown. The brown O-rings are generally auto fuel resistant, but their tolerance for the newer oxygenated auto fuels is unknown. The older (black) O-rings are no longer available. Upgrading to the newer O-rings requires replacing the fuel cap. New fuel caps with brown O-rings are available and fit all the receptacles installed in the tanks.

CAUTION! If the T-406A replacement cap is to be used on the RV-12/12iS, it must be modified in accordance with the RV-12 construction manual (Section 37) to allow venting.