that sounds like the oring, when you have 3/4 full or more, it's leaking from teh top.

 

Mine leaks a little as well

 

does anyone know of a part number or O ring that doesn't expland out so easily?

 

It doesn't expand unless it gets wet, it is always recommended to replace it with a new when the pump is removed, I did that when I had such a leak and have had no issues.

 

OEM part number listed here, but I dont know of an alternative one:

https://my350z.com/forum/showthread....ghlight=o-ring

 

have you guys had further problems after the new o ring?

 

^ good question... I haven't filled the tank up since to find out! LOL!

 

Mine was fixed 100%, no more leaks. It is not the fault of the oring it is the fault of the installer, either he/she did not ensure the oring was in its place correctly or failed to replace it with a new one after getting wet with fuel and expanding.

 

I had the same issue after installing my APS kit. Changed the Oring and still had a gas leak when I filled up. While I was at Forged Performance getting a tune, I mentioned this to Sharif and they pulled out the gas pump to check things out. Turns out the return hose connetion was a lot of the problem. Sharif can explain better, but there is a web pattern in the plastic (underside of cap) that needs to be ground smooth to get a good seal. Sharif reworked this connection and replaced the Oring and problem fixed ... no more gas leak or smell even after topping off a full tank.

 

I replace my O-ring today and made sure everything was good to go. Gas smell is worse now. Im thinking its not the O-ring but the fuel return line instead.