Can you see the leaky lines under the car? There are two steel fuel lines leading up to the engine, and where they connect to the tank, they are flexible. Are these the leaky lines? I ask because from where you're describing the leak location (from the spare tire) it sounds like the leak may be coming from the lines leading from the main tank to the expansion tank...it a small metal tank just forward of the spare tire...you can see it when you pull off the spare tire cover. On my car I don't think I can see these lines from underneath...I may be wrong though. But you would have to pull up your rear seat (3rd row seat) if you have one or just the rear floor liner, to get to one end of these lines...and the other end is at the expansion tank. On mine, they run between the top of the fuel tank and the bottom of the car floor, so they're probably hard to run. Just a guess, but it my require you lowering the tank a bit.

The good news is you don't have to worry about introducing air into the fuel system if its those hoses. If you don't disconnect the flexible lines that connect the tank to the steel lines, you'll be all right as far as air goes.

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now