Hello - I currently have a 1973 Ranchero, and previously owned another 1973 and a 1979. When I fill this one with gas, it is impossible to do so without having it overflow on the ground when the overflow valve on the handle engages. I have tried multiple pumps, have tried going slow, have tried going fast, have tried different angles - and it always overflows at least 1/4 cup of gas from the fill hole, sometimes more. I am not trying to top it off. Is this problem typical?

I don't recall my other Rancheros doing this, but perhaps they did - I had them quite a while ago. I'm just waiting for some panicky station attendant to call hazmat, though it would probably evaporate before they ever got there. I tend not to worry too much about what hits the ground, but it also runs down my fender. I know that I can just not fill it completely - but that's hard to estimate and since my mileage sucks I need as much in there as I can get.

Thoughts?

 

Get under the car and check the breather vent tube. It is most likely plugged with dirt. It usually goes from the tanks sending unit up to the frame. If it is plugged, there is no place for the air to escape as you fill the tank. You might have to see if you can blow air back into the tank to see if it is blocked.

 

Thanks - that makes sense!

 

OK - I believe that that vent tube connects to a charcoal cannister up front. Could the cannister be plugged? Where does it go from the cannister? Thanks!

 

Yes those canisters can get plugged, but usually they do not cause the problem. Make sure there is not a second vent line that usually clamps onto the frame above the differential.
You could also disconnect the rubber hose line that connects to the canister. Leave off til next fil and see what happens.
The cainsters and to help take gas fumes from the tank and filetr them out and back tothe carb to help burn all the gas. Most people just disconnect them and do not bother using them. It was something that was suppose to help with fuel and the enviroment. They are finnicky and do not work most of the time.
But pull the hose off where it connects to the steel tube to the cannister, nearest the gas tank. The steel tubing can corrode and plug up, if this helps in venting for filling.