94 4x4 Cummins sprung a fuel leak in the fuel return line. Mechanic replaced the line and relaced the fuel filter while he was in the area. A few months later the truck began spewing fuel again. Took it back to same mechanic. He said filter was loose. Last month it started leaking fuel again. I crawled under and looked. Fuel was streaming from the edge of the water sensor. I removed the filter to get to the sensor. When I pulled the water sensor off the fuel filter I found an O ring that was doing nothing but occuping space. I replaced the Car Quest Filter with a Purolater fuel filter. The O ring for the water sensor and all the physical interfaces were significantly different. Anyone else had any problems with Car Quest fuel filters or is this simply an incompetent mechanic?