Farmall Cub

I found that the radiator cap for my '40 H is missing half the gasket. What's strange is the missing piece is gone (and not inside the radiator), so I'm guessing the prior owner got rid of the piece. From what I read, this model is the pressurized system, so I want to replace the gasket.

I have not found a direct replacement without buying a whole $20 cap that I don't really need. I have not had an overheating problem, in fact, I need to check the sensor because the temp gauge never moves.

Anyway, does anyone know where you can get just the gasket? Thanks in advance!

I think your best bet is going to be to replace the cap.

Ok, thanks. I was afraid of that. The owner's manual talks about replacing the gasket, but that was 82 years ago.

I wonder if perhaps you could get a small piece of rubber gasket material and cut one out. You might have to stretch it a bit to get it past the check valve.

I thought about that and it may work, but I don't have anything like that around and I see the gasket itself isn't flat. If you click on the picture to make it bigger you can see it's kind of shaped with ridges. I'm assuming that may be necessary since the factory did it that way and I see the replacement caps look that way as well.

What about trying a piece cut from an inner tube?

Those ridges have been formed over time, I think it started out flat.

I guess I need to correct myself, when I looked up a pic of the cap, it indeed has ridges.