The Ford Barn

Floats · 06-22-2022, 07:03 AM

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 · 06-22-2022, 09:41 AM

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

Y-Blockhead · 06-22-2022, 11:09 PM

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...lig_dp_it&th=1

rotorwrench · 06-25-2022, 08:18 AM

Sponsored Links (Register now to hide all advertisements)

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.

06-22-2022, 07:03 AM	#1
Floats Senior Member Join Date: Dec 2013 Location: Mossel Bay, about 300km from Cape Town Posts: 530	Model A fuel shut off thread 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 __________________ Regards Chris Cape Town 28 Model A RPU, 29 Chevy Phaeton, 67 E Type FHC, 67 250SL Pagoda, 83 911 SC

06-22-2022, 09:41 AM	#2
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 5,044	Re: Model A fuel shut off thread IIRC, it's 3/8" NPT (National Pipe Taper), If not 3/8" it's 1/4" __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn!

06-22-2022, 11:09 PM	#3
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 5,849	Re: Model A fuel shut off thread 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...lig_dp_it&th=1 Last edited by Y-Blockhead; 06-23-2022 at 08:56 AM.

06-25-2022, 08:18 AM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,431	Re: Model A fuel shut off thread Sponsored Links (Register now to hide all advertisements) 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.