Model A fuel shut off thread

[Floats]

Hi guys,
Could anyone give me the size and thread of the Model A shut off valve. This is the approximate 1/2 inch end which screws into the bottom of the fuel tank.
Mine is cross threaded, stripped and leaking badly.
Much appreciated
Chris
Cape Town

 

[katy]

IIRC, it's 3/8" NPT (National Pipe Taper), If not 3/8" it's 1/4"

 

[Y-Blockhead]

It is ¼" NPT. Be careful not to tap too deeply, making the hole too large. Then you will have a real problem.

I have found Permatex thread sealant works well. https://www.amazon.com/dp/B0002UEOP0/?tag=atomicindus08-20

 

[rotorwrench]

I used to do a lot of tapered pipe threading and repairs for aircraft fittings. I would drill a base size hole to fit the most narrow portion of the thread and then use a tapered reamer to adjust for the correct thread angle. I would then start the tap cutting process. A person has to take care not to get the taped bore either too deep or too shallow but this keeps the tap from having to cut too much material. It takes careful measuring to get it just right.

Tapered thread Heli-Coils are available for repairs but a person has to practice it a few times to get it exactly right. Parts can be ruined pretty quickly if a person isn't real careful.