I was going to install this return line bung fitting kit
I was going to make a little access hole on the trunk of my hatch to get access to the top of the tank to drill and install the fitting . But was wondering if I can drill and install the return fitting at the bottom or the gas tank ?
You can buy that fitting, but the ideal way is to just bite the bullet, drop the tank (which is like 5 mins), then run a bulkhead fitting with a tube that allows the fuel to return from the top, down to the bottom of the tank. This will keep bubbles from forming.
If you just run the return directly to the bottom, and not from the top, the pump has to overcome the head pressure from the fuel in the tank, which will change from when the tank is full to when it’s empty.
I’d use a fitting like this one, then run a compression style an adaptor with a 3/8 tube running down inside the tank. Best way to do it.