New to me - truck. Gas smell - not really in cab out outside truck, - gas cap feels tight but gasket is a little dry.
Haven't noticed any leaks yet.


Scott

 

These trucks require a vented gas cap to be used with the original tanks. Otherwise, they build pressure (cab heating up from the sun) or vacuum (fuel pump drawing gas out of the tank without air replacing it).

So, you can get a bit of a gas odor coming from the cap. If you fill the tank full and park it on a level surface on a hot day they can easily overflow as the fuel expands in the heat of the day. A new gasket on the cap might help a little.

There is a check-valve inside of the cap, but it only comes into play on a hard right-hand corner so gas doesn't slosh out of the cap vent. Once the corner is completed the check valve would drop back into place so that air can once again pass.

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If it's leaking at the carb, it's likely to vaporize into the air before it drips to the ground. What carb are you running?

 

There's a neoprene fuel filler hose clamped between the fuel filler neck and the in-cab fuel tank. It hardens up, then begins to crack...allowing gas vapors to waft inside the cab.

Depending how badly cracked the hose is, the gas smell can also be detected outside the cab.

Vapors can also waft from the fuel tank sending unit gasket, which is cork. Cork shrinks with age.

Pic: 9080 is the fuel filler tube grommet, 9034 is the fuel filler tube, 9047 is the filler hose. The grommet & filler hose are reproduced.

The 9276 fuel sender gasket is available NOS & from auto parts stores. The fuel sending unit and its gasket are the same for all 1961/77 in-cab fuel tanks.

 

Scott, Welcome to FTE!!

If the truck has been setting for an extended period of time then the odor may be a result of the gasoline morphing into some type of petroleum jelly, if the case, suggest drain and flush tank. If the truck is/has been setting in the heat then the hoses, and clamps me be seeping due to expansion; speaking from experience, make sure the truck is not parked slanted towards the filter neck side at anytime if possible but in particular on a hot day. Otherwise, suggest check clamps on the 'filler hose' linking the 'filler neck' to the tank, if the hose is weathered, suggest replacing, runs around $10. The other possible problem area is where the hose connects to the metal tube running from the tank, check the fitness of the clamp and if the hose appears weathered then replace the 3-4 ft. gasoline approved hose. Although the fuel pump on my 65 has an internal fuel filter I ran the rubber hose to a canister type fuel filter mounted on the inner fender, then to the fuel pump.

For info purposes, and speaking from experi

Again, welcome to FTE, looking forward to your input/suggestions, and post pic's if and when U can.

 

I may have read it wrong, but I thought he said

Gas smell - not really in cab out outside truck

Probably meant to read

Gas smell - not really in cab but outside truck

So, I assumed it was not a strong odor inside of the cab. As you guys know if the leak is inside of the cab then the seat and everything starts to reek pretty badly as the smell is trapped inside of the cab. Usually makes it tough to even get in and sit inside of the cab.

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But when the filler hose cracks, the vapor smell can be inside or possibly outside...especially when the drivers door is opened.

I'm speaking from experience...how many years have you owned these trucks? I owned one for 44 years, buying it new March 1965, selling it November 2009.

 

The entire rubber filler hose is inside of the cab so you absolutely WILL smell gas INSIDE of the cab.

I own 3 of these trucks and have been intimately familiar with several others since they were brand new, so ya, a bit of experience over here, too. Thanks for asking.

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But you'd agree there is something defective with the hose or gaskets if there are fuel odors inside (or outside for that matter) the cab, correct?

 

Meanwhile back at the ranch waiting patiently for the original author to respond...

Ya'll crack me up with your ever continuing arguing against assume-ations brought right out of thin air.

And who ever said "Inside the cab"? TA4550 did at first but took it back.

The rest of you carry on! Please!

I assure you all this has absolutely nothing to do with the filler hose... We all know how obviously those are from "INSIDE" the cab.

 

The exception that I mentioned was the gas cap itself, which is vented. So from outside of the truck it would not be uncommon to smell some gas fumes coming from the vented gas cap. Especially on a hot day when the gas is potentially overflowing onto the ground.

Actually on a hot day you can stand back at the correct angle to the sun and see the gas vapors from the gas cap going into the air if conditions are just right.

Otherwise, sure, I agree.

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First - thanks for all the enthusiastic replies
Yes I meant that the gas smell is more noticable outside the cab. In fact it makes the garage smell. Honestly not positive about which carb it is - two barrel and I assume Ford not Holley BUT not sure.
My experience is rather limited with older Trucks. I first helped my Dad but a 1964 F100 in 1974 which he used (and I drove a bit) for about 3 years. He then bought a used 69 F250 in 1977 which he keep until 2005 and I drove that one several times over the years - a straight six - single barrel carb.

I have checked the inside hose from tank to filler and the gasket around the filler - both appear fine. The gas cap is a NON vented type so I will replace that first.

Scott

 

Amen.


John