I just did a neat job a replacing the pump on my 95 850 which as it turns out was not what ails it (the car has 400k kms so it may be dead and not merely ailing). I made a tool to remove the ring with four 1/4-20 screws and a piece of mdf - a 3-7/8" dia. disc with the screws at the four points of the compass on a 3-5/16" circle, a 1/2" square hole in the centre for my ratchet extension, the screws extending at least .7" from the disc. I didn't need the tool to install the new ring, used a large flat-bladed screwdriver and a hammer. I used a (flat) bicycle multi-tool to pull up on the connections on the fuel lines and lubricated the seal and the output/return connections on the pumpm with silicon grease. Very easy straightforward repair, just not the right one.

Good luck and best regards,

Glen / Beauregard