Gas fumes?

J

JupiterBandit

Member
I have a 1931 Model A and I can smell strong gas fumes from the car when driving it. I understand that the tank is in my face but is it normal to smell raw gas inside the car?

I see no signs of leaks coming from the fuel gauge and the on off valve is under the bonnet. It's a late model 31.

I was wondering is it possible the cap seal is not sealing? I would assume this tank is vented in some manner.

Any thoughts would be appreciated.
 
Tank is vented and the vent is right on the cap itself -which is right in front of your windshield. Do you have your windshield open when you're smelling it?

You might try finding the vent hole and plugging it for a test. Your car will run for a while before a vacuum forms in the tank preventing the gas from going down to the carburetor.

Another leak that some don't think about is the bracket for the steering column. Don't know if you have the bracket that goes back to the dash rail, or the earlier bracket attached to the tank. Gas is wont to dribble down the steering column - right in your lap in effect - hence a strong smell.

I used to have a drip on the rubber mat directly below the inside shutoff valve. You have a compression fitting in a similar location but you may not see (or feel) a drip.

Gas gauge is always suspect. And given the right tools and gaskets (I like the original cork gaskets with some permatex to help seal) you can fix or re-do this easily to eliminate it from consideration.

Hairline cracks or rust throughs from the inside have happened before - but you'd see evidence at the lowest point of the tank - or directly below it. Bubbling paint usually precedes the rust throughs.

Keep checking around. A faint "Model A" odor is normal (I always assumed this a mix of the smell of quality along with some gas fume) but it should not be overpowering.

Joe K
 
Gas fumes while driving<try closing the windshield,odor not gone,remove dash and check for leak at gauge.
 
As has been said, make sure that your gas gage is tight and sealed. For some reason lots of guys like to fiddle with it and leave it finger tight. True, it DOES make it easier to get into the next time (how many times do you need to get into it?) but few things will freak you out more than seeing gas leak out around that gage after filling up, while driving down the road. Sure hope there are no sparks nearby..... Also, your compression fittings on the fuel line starting from the shutoff valve may be slowly "seeping" and causing the smell.
 
I should of posted it was a Roadster and I never drive with the Top up.

I will replace the cap seal and see if that helps. I will also check under the dash to see if I can see anything. I'll take some pictures and post them tomorrow.
 
I agree with Mike V. If you are smelling gas then there is a culprit somewhere. You probably have a fitting that has a small drip somewhere. Just check any fitting that has to do with gas. If that is not it, try a different gas cap and see if that does it. Also make sure that no gas is running out of your carb while running and giving it the gas.
 
The pan under the Carb is constantly wet, it doesn't smell like gas when I look at it but I didn't put my nose in it. I notice that the carb leaks from where all the different linkages go into the carb. I mean it's not pouring out or dripping it's just wet. Could that cause the gas fume smell into the car. I would think it smells more like it's actually leaking inside the car
 
Jupiter, those fumes will come right through your firewall and into the car. Do you have another carb you could put on and then wipe everything clean and dry that it dripped on and then take a stroll and see if that helps..
 
JupiterBandit said:
I need another carb. I wish I could find a nice late 31 with the side bowl already rebuilt
Click to expand...

The good news is that there are plenty of places to get a rebuilt, well operating carb. Yeah 'wet below the carb' is definite evidence that something is wrong/smells :) ! Your lucky if that is all there is to the 'smelling gas fumes' notion. I just figure that it's the ....nature of the beast ! Luckily, in a roadster without top up, you have the best draft situation. I think that I eventually figured out WHY some wore goggles and slickers (long coats) when driving roadsters ..back when, i.e.-fumes/dust, and bugs in teeth :D !
 
hardtimes said:
The good news is that there are plenty of places to get a rebuilt, well operating carb. Yeah 'wet below the carb' is definite evidence that something is wrong/smells :) ! Your lucky if that is all there is to the 'smelling gas fumes' notion. I just figure that it's the ....nature of the beast ! Luckily, in a roadster without top up, you have the best draft situation. I think that I eventually figured out WHY some wore goggles and slickers (long coats) when driving roadsters ..back when, i.e.-fumes/dust, and bugs in teeth :D !
Click to expand...


LOL that makes sense.

I drained the tank and the whole inside is nice and shiny. There wasn't any debris at the bottom either. I may plug the tank and put 5lbs of air in there and see if there is anything not right. As for the carb I'm going to go ahead and replace it with a rebuilt one. The current one doesn't have the side bowl and being a late 31 I'm told it should. Although I've read that not all late 31's had the side bowl on them since there were 3 different manufactures making the Zenith carbs for Ford.
 
JupiterBandit said:
LOL that makes sense.

I drained the tank and the whole inside is nice and shiny. There wasn't any debris at the bottom either. I may plug the tank and put 5lbs of air in there and see if there is anything not right. As for the carb I'm going to go ahead and replace it with a rebuilt one. The current one doesn't have the side bowl and being a late 31 I'm told it should. Although I've read that not all late 31's had the side bowl on them since there were 3 different manufactures making the Zenith carbs for Ford.
Click to expand...

Because your fuel shut-off valve is under the hood, your '31 should have a side bowl carb. It serves as your filter/strainer. Unless you have added some aftermarket inline filter, you will have nothing to keep junk out of the carb. That's the purpose of the side bowl.

It is true that Ford had contracts with several different manufacturers for the Zenith carbs. However, it doesn't matter who made the late-31 carb for Ford, it would have the side bowl strainer.
 
I've installed the aftermarket little shutoff filter in Model A's with indented firewalls. It fit and worked fine.

I wouldn't go as high as 5 pounds pressure to test the tank.
 
if you have access to an emissions analyzer with a gas bench use the probe // sniffer to detect the fuel leak. the HC's will skyrocket
it can also seep out the gauge and run behind the dash panel then dry up
 
Joe K said:
. . . Another leak that some don't think about is the bracket for the steering column. Don't know if you have the bracket that goes back to the dash rail, or the earlier bracket attached to the tank. Gas is wont to dribble down the steering column - right in your lap in effect - hence a strong smell. . . .

Joe K
Click to expand...

Jupiter, do you have the later '31 steering column bracket or the earlier '31 bracket Joe mentioned? That would be my bet. But that could be because I too had a strong gas smell inside the car and am in the process of fixing that very thing! For me it involves removing and cleaning the tank, coating the inside with a sealer made for that purpose and replacing the bracket with the later 31 style. Task is not yet complete so I am hopeful results will be favorable.
 
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