Just an update. Tried the trick with silicone carbide sand paper and oil. Used 800 grit, then finished with 1000 grit, using a flat piece of steel as the backing. My first try was unsuccessful, and it leaked worse then ever. Took it off again, lightly sanded, and cleaned up the injector contact surface real well. Worked like a charm the second time. Must of had a piece of dirt under the fitting the first time. Thanks very much for your help.