I had to drop the fuel tank on my 1970 Cutlass Supreme to replace sending unit. The sending unit being replaced has 2 fuel lines coming from it. The question I have is what are the 2 fuel tank vent hoses coming from corner of tank supposed to be connected to? Both were just open not connected to anything. I expect some pollution item was removed. Should these be capped or what should I do? Having these hoses open does not seem like a good idea.

 

Its a plastic vent that has the two hoses connected to it and something like cotton inside it. There should be a tab on the underside of the trunk floor that holds this vent in place.

 

The reproduction companies have them, but it should look like this:

 

There wont be cotton in there, it will be foam to act as a filter.

 

Thanks for all the help. That is exactly what I need. Just looked again. I see the bracket and I have a dried out piece of plastic in the tubes

 

Interesting, my '70 fuel sender has only 1 tube - fuel line only. Primitive by today's standards, emission control (fuel vapor return line) must have been added in later 1970 production. I thought this didn't occur until 1971.

 

A '68 442 will have two lines on the sender. A '68 Cutlass will only have one line. Probably the same for '70 as well.

 

The OP has a 1970 Cutlass Supreme with 2 lines on the sender. I have a 1970 Cutlass Supreme with 1 line on the sender.

 

Maybe his car has or had a 455, big block with fuel return line, small block with no return line.

 

Does anyone know if this filter needs replaced from time to time? I just tried to fill up my car and gas kept coughing back out of the tank. My filter is about 10 years old

 

The vapor canister was required on cars delivered to California dealers on and after Jan 1 1970 and the rest of the country had the requirement for 1971 model production.

 

My build date is August 1969, early '70 production model year.

 

It's a vent or air breather tube, with a cotton-like wad inside the plastic tube. Allows the gas tank to fill and drain easier, like a hole in the opposite side of a can for easier pouring. The '70 OE gas cap is non-vented. My '50-year old vent tube was not clogged, but I'm replacing it with a new tank. I can't imagine yours being clogged in just 10 years, unless perhaps you're in a very dusty climate and you drive a lot. It's tucked up way underneath so it's not likely to get plugged by dirt. Can you get under your car, remove and inspect it? Is it possible the gas nozzle at the gas station was simply pumping more volume than your tank could accept?

Edit: The neck of the tank does have a metal catch inside to hold the pump nozzle which can restrict the flow of pumped gas.