I just went through this on my 740. The fittings were well rusted but did release after applying a penetrant (used in the aircraft industry I think) and leaving for 5 minutes. I was lucky. I made a mental note to poke around the whole car every year to work various fittings prone to rusting or at least to apply some penetrant and some RustCheck. Bleeder screws are another example.

Frequent maintenance really is the best way. Course, with my luck, I will probably cause more damage than I am preventing. Murphy never sleeps.

Bill
--
Volvo Info Site 1990 745GLE 16valve

WD40 does not work well as a penetrating oil- it was designed to displace water. Get some PB Blaster or Kroil and let it soak for a day or two and make several applications. You will help it work if you brush off accumulated dirt and rust from the application site.

I have, at times, resorted to an impact gun to break these fittings loose. At any rate make sure you are using a box end rather than an open end wrench (and a 6 point box end is even better). I have found it easiest to go to the extra work of removing the whole assembly to the bench for easier working conditions and space. Be prepared to plug the inlet line as gasoline flows out due to gravity. Always be prepared for the worst case when dealing with potentially dangerous activities like fuel spills and leaks.

Hopefully you got new copper washers with the new fuel filter. Always check as soon as you start up the car for leaks from a newly installed filter. I have found it counter productive to try to hold the filter by the hex shaped form at the one end. The aluminum case of the filter is easily punctured with the slip of the wrench. I use a very BIG pair of adjustable pliers to hold the filter by it's built up seam.

Randy

I soaked mine with PB Blaster for a couple of days before trying the wrenches.

Your's sound worse....may have to cut them off and start over with new fittings?

Good Luck,
Chris