I replaced the fuel pump on a friends 96 blazer. A few days later he noticed fuel would spill out the top when he filled it up. We finally dropped the tank again, and removed the fuel pump. I found the rubber O ring was stretched out and did not fit the opening. We found another one at a local shop (used), but it was about a 1/2" smaller in diameter. It fit perfect. We lubed up the O ring and the fuel pump with vaseline and pushed into the opening. It took 2 of us to get it pushed down and the C-clip back on. I felt good about the process and fit of the O-ring. We put everything back together and filled the tank. The same thing happened. Is this a common problem? Any ideas how to fix? Thanks

 

Not a common problem. I think you need to call the dealer and get a factory seal. Try not using any lubricant the next time.

 

Not a bad idea. I was hoping a few others may have had experience at this and reply. I find it hard to believe that vaseline would keep it from sealing. I'm not talking a little bit of gas leaks, but at least a gallon comes pouring out rather quickly.