Fuel shut-off thread size

shall

shall

Member
Well, while trying to remove my leaking shut-off valve I twisted the top threads in half and now need to drill the old brass part out of the tank, and probably re-thread it for the new shut off valve. Anyone run into this before and/or know the size die that I should use?

(1929)

Thanks in advance!

Steve
 
I would not drill it out, but try to find a good easy out, and not one of those cheap tapered reverse sprial things. A much better choise is a square taper with sharp barbed edges. Or ask the Snap On driver to see what he has for sale. There are also some with a straight shaft with sharp gripping edges running lengthwise.

For anyone needing to remove the tank valve, it's very important to use BOTH hands and press forward on the valve while you pull with the wrench handle toward yourself. You are trying to keep all the pressure in a rotating motion, and not so much pushing sideways, which is what breaks the fittings.
 
Be warned, when you buy a 1/4" NPT tap you will need a tap wrench which fits larger than a 1/2" tap. I found this out the hard way, in fact I'm still looking for a wrench to fit mine.
 
Thanks all. Easy out wouldn't do the trick so drilled (small). Basically have a brass sleeve in there now to deal with. Thought maybe the heat from the drilling would free it up but no luck. I'll check NAPA...and pick up some #2 permatex while there. :)
 
MrTube said:
Be warned, when you buy a 1/4" NPT tap you will need a tap wrench which fits larger than a 1/2" tap. I found this out the hard way, in fact I'm still looking for a wrench to fit mine.
Click to expand...
An 8 or 12 point socket of the right size will suffice.
 
Tapped out the fuel tank last night and all went well. Leak free and the shut off actually shuts off!

Thanks Gordb for the tap size and Bill Williamson for the socket trick. I used a 12pt 3/8" which seemed to fit the tap handle end nice and snug.
 
Last edited:
With taps I like to press a nut on them & then can use them w /a ratchet or extension if needed.Just find a nut a little smaller than the square end & press the nut on in the vice.
 
Les Andrews book #1 - in two places says the thread size is 1/2" pipe thread...:confused: (for all shut offs, including fire wall late 31).

I have a early 31 roadster...

I got my shut off out without breaking it, but the threads seem a bit fudged - I was planning to run a tap into the tank to clean up that side and use a die to clean up the valve side...

Any Comments, precautions or other advice appreciated.

Thanks
 
Last edited:
The thread size is 1/4" pipe thread. I'd just run the tap until it starts to bite, then back out. You just want the threads straight, and not cut new threads. I use a bit of pipe dope on the threads for the fitting.
 
You must log in or register to reply here.
Back
Top