fuel sender gauge gasket

Just finished installing my new sending unit so heres a few helpful tips. I measured the new unit retaining ring and the old one. The new one is 1.1 mm and the old one is 1.5mm, so I used the original thicker one. I didn't have a brass drift but I ground off the tip of an aluminum gutter nail, worked great. I also installed with Vaseline on both sides of the gasket, on the rim of the sending unit and on the retaining ring. It'll help everything to slide together, keep the gasket flexible longer and any on the inside will just dissolve in the gas without plugging filters or carb. BTW I'm replacing the sending unit I installed 20 years ago and the gasket is still flexible and the metal mating surfaces were shiny. I was able to lift the car and create a siphon to drain the tank, lowered the fuel level below the opening in the tank. I also wired in the new sending unit with alligator clips to make sure that was the problem. Just finished dash issues on another car and didn't want to replace the sending unit when the guage was the problem. Hope this helps.