I have a 2007 850D, and I think the mechanical fuel pump is going bad. Rather than pay JD over $100 for a new mechanical fuel pump, I'm going to install an electric fuel pump just like my JD 4300 and 455 tractors. The question I have is what to do with the old mechanical pump. Should I just leave it where it is, possibly short the in and out lines together, or remove it completely and make a cover plate to prevent dirt from entering the cam drive in the bottom of the injector pump.