28-29 gas cap

[1955cj5]

I read the current thread on gas caps but it covers the later models...

The judging standards book (15-5)mentions two styles of early gas cap. One with a single vent hole in the middle and the other with three.

Mine has a single hole but no internal baffle. Is mine correct or just some aftermarket cap? The hole appears to be cast in and not just drilled by someone along the way...But it appears to be allowing some leakage or maybe condensation to seep by...

Does someone have a picture other than the one in the judging standards of a single vent hole cap? They show a three hole cap on page 15-6...

Thanks

Randy

[Tom Wesenberg]

I just tried the search box to find pictures I posted of original gas and radiator caps taken apart, but had no luck in finding the thread.

The cap pictured is an aftermarket cap. The original caps had a threaded inside liner soldered to the outer cap which is made of brass. The venting for the gas cap travels between the two parts and exits at the bottom of the threaded part through 6 small slots.

https://www.fordbarn.com/forum/showth...ictures+solder

[Tudortomnz]

Yes, that does look like a repro cap.
The vented gas caps came in at least 2 versions. One with a single central dome & another with circular venting is shown in the Service bulletins.

[Ed Saniewski]

Randy, I had the same problem with gasoline splashing around, and seeping out. I took some cork and made a solid round gasket with three vent small holes, Place the gasket in the cap with the gasket washer that came with the cap. no more problems.

[JohnLaVoy]

Here are two originals you can see how the single hole differs from what you have.

[1955cj5]

Sponsored Links (Register now to hide all advertisements)

Thanks everyone...now i know what I have and the pictures show me what I need to shop around for but for now I will try Ed's idea of an additional solid cork gasket with holes...

The radiator cap looks identical but without the vent hole...maybe they came as a set...

[JohnLaVoy]

You might have a radiator cap, there are no vent holes in that and it won't work as a gas cap. They look the same and have the same threads just no vent in the radiator cap.

[supergnat]

I have an original like the one in the rh side of the photo. How can I test it? As a result of this post I found that my gas and radiator caps were switched. Luckily i haven't experienced any problems.
Thanks

[Tom Wesenberg]

Originally Posted by supergnat

I have an original like the one in the rh side of the photo. How can I test it? As a result of this post I found that my gas and radiator caps were switched. Luckily i haven't experienced any problems.
Thanks

Use a foot long rubber hose and place one end over the center hole, and blow into the other end. If you can't blow, then it's plugged or it's a radiator cap.

[supergnat]

Thanks for the tip Tom. I removed my cap and performed the test. Mine is clogged. I tried clearing it with spray carb cleaner but so far no luck. I also cleaned the slots with an Exacto knife and spray carb cleaner without success. Can I soak it in the bucket type carb cleaner or would that damage the finish? A photo is attached.
Thanks

[dean from bozeman]

John LaVoy and supergnat have fine photos of the "one hole variety". Please look in your stashes of gas caps and see if you can find the earliest variety which is almost identical but has a smaller hole.

To see what I am talking about look in the Ford Service Bulletins for June, 1928 page 257 Fig. 520. There you will see a comparison between the gasoline tank and radiator filler caps. The gas cap illustration shows the smaller hole in the one hole gas cap.

Sorry that I have no photo to show you. Here in Montana I only have the large hole gas cap. A495 does have a small hole cap but unfortunately I don't have a good photo of it. By next summer I will have a photo of one and hope to have samples comparing the hole sizes at the seminar.

[Tom Wesenberg]

Originally Posted by supergnat

Thanks for the tip Tom. I removed my cap and performed the test. Mine is clogged. I tried clearing it with spray carb cleaner but so far no luck. I also cleaned the slots with an Exacto knife and spray carb cleaner without success. Can I soak it in the bucket type carb cleaner or would that damage the finish? A photo is attached.
Thanks

Your cap looks like a radiator cap. The gas cap needs a path from the vent holes to the outside 6 slots, as shown in the picture above.