I changed the fuel pump in my 00 Silverado with an aftermarket one. As I've read here alot of folks have encountered a problem getting the pump to seal with the new rubber O-ring. I had the same problem. The new O-ring is slightly thicker than stock.
What problems will/could I encounter running it without the rubber O-ring? I'm going to have to shave down the aftermarket one or see if I can purchase a stock O-ring only.
But for the time being, can I run it without the rubber O-ring?
Thanks!

 

Without the o-ring, gas could come out of the tank and possibly cause a fire. It would be a safety issue!

 

No, that's a seal you need. It fits, it's a pain in the a$$ but it fits. You need someone to push down the top of the pump itself, and then you get a chisel or a punch and a hammer and you have to basically beat the metal plate back on. It takes patience but it does fit. I've replaced numerous ones in 99-02 chevy trucks and it all was the same