I have a 2005 999. I have replaced the fuel filter and I have pinched 2 o-rings trying to bolt it down. I have put grease on them but I can't seem to get the o-ring to seat properly. It wants to roll down. Is there some Technic to do this? Thanks.
Haven't messed with a 999 type flange, but what I do on the 916 / ST style is only grease the tank side of the ring. I don't grease the the area that touches the pump flange. It goes on dry, then I lube the outer ring surface and the tank surface. Very important to have it go one as square as possible too. Again, not sure about the 999 set up, but with the older flanges you can use longer screws and walk it on by tightening the screws a little at a time in a cross pattern. Once the ring has pressed in, just push it in by hand the rest of the way.
The other important thing to check is that the tank surface has no burs. I have wet sanded / polished mine. Nice and smooth.