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TR2/3/3A Can someone confirm size and thread count on fuel line tube nuts [brass fittings]?

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TuffTR250

Jedi Warrior
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Can someone confirm the size and thread count on the "tube nuts" (brass fittings) going into and out of the TR3A fuel pump? I do not have a fuel tap. I have 5/16 inch fuel line going into fuel pump and 1/4 inch pipe going out of fuel pump to carbs. I believe both "tube nuts" (brass fittings) are size 1/2 inch with 20 threads per inch. I believe the only difference in the two "tube nuts" is the inside diameter of the "tube nut" to fit the different size pipes, i.e. 1/4 inch and 5/16 inch. Is this correct? Thanks!
Bob
 
I don't have the thread information handy; but you're right about the nuts. The outlet is a special adapter nut, to fit 1/4" od tubing into what would normally be a 5/16" fitting.

Fairly standard trick at the time, I even once managed to buy one of the special nuts at FLAPS from one of those "wall of bins" assortments.

The problem is that the pump fitting was designed for a different compression sleeve. Modern sleeves are too short, and allow the nut to bottom in the threads before properly compressing the sleeve. Here's one man's solution:
https://drive.google.com/open?id=0B2H2NJt34OffODA0ZmI4YTItNDhiZC00YmMzLTllOTUtZWVjN2U5MTUzZjA3
 
Thanks Randall!! That's very useful information about the compression sleeves.

I see that Moss lists a tube nut for the 1/4 inch outlet pipe, p/n 376-575, and compression sleeve 376-565. I wonder if those are actually "correct" for a TR3? Has anyone tried them?
Unfortunately Moss has the short pipe and tube nut for the 5/16 inch pipe as NA.
Bob
 
It's been a long time ago, but the sleeve I got from Moss was just a standard compression sleeve, meaning it didn't work right. Didn't try their nut.

And maybe they have since found a source for correct sleeves.
 
I purchased both tube nuts from TRF and have used them for several years. They sell the sleeves as well. But I suspect they are the same as found at the local hardware store. Again I have used regular sleeves with only minimal problems, namely reusing them several times. After several tightenings I had some leaks.
 
Randall, the PDF you posted on making a special compression fitting mentioned that the 2 piece fabricated compression fitting should be the same length as the original, but unfortunately I did not have the original fitting on my TR3 so I don't know the length. Can you tell me the correct length for the 2 piece fabricated fitting? Also, any idea of the measurement for the end resultant outside diameter of the flattened area? Thanks!

Charley, can you tell me the TRF part numbers for each of the two tube nuts that are used for the fuel pump. I could not find the p/n's on their web site catalog, nor in my TR2-3 parts catalog. Thanks!
Bob
 
I talked to Albert at TRF. Here are the TRF p/n's. He said they buy the compression sleeves from a reliable source, not general hardware store, but did not know the length of them.
>5/16" tube nut is 60142, and 5/16" compression sleeve is TL8
>1/4" tube nut is 60176, and 1/4" compression sleeve is 102729

He said both the tube nut and compression sleeves are the same p/n's for TR3, TR4, TR250, and TR6.
Bob
>
 
Very good Bob. By the time I saw your message and got the numbers you already found them. The second thing that I was going to say was, if you can not find the part or number on line call them at TRF and they can usually get the part number for you. It would be interesting to know how many parts they have in stock that they do not show in any printed catalog or on the on-line catalogs.
 
Sorry, I thought I had an original 1/4" sleeve to measure, but couldn't find it.

TL8 is a standard sleeve, the ST hardware catalog gives length as .250" (1/4")

TRF stocks a LOT of parts that are not listed anywhere except in their database. The trick is to look them up in the factory spare parts catalogue, then use that part number to search the TRF database.
https://secure.zeni.net/trf/

Unfortunately, that doesn't work in this case, because the TR3 SPC only lists the assemblies (tube, sleeve and nut), not the individual parts. I'll try to fix that, in the copy I maintain. TRF does show them though, in their online TR6 catalog (which is much more complete than any TR3 catalog they've ever published).
 
Regarding the 1/4 inch fitting on the fuel pump this has been my experience as of 2 years ago.

TRF 102729 - This is a standard olive for 1/4 inch tubing. It is 1/4 inch ID and the width is the same as any hardware store 1/4 inch tube fitting (1/4 inch in length).

Moss 376-565 - This is also a standard hardware store olive same as the TRF 102729.

Moss 376-575 - This is a tubing nut with a 1/4 inch hole and the nut has longer length versus a standard 1/4 inch tubing nut. At the very end of the nut is an unthreaded section. Measuring from the threaded side of the wrench hex to the end of the fitting, the Moss nut is about 3/32 inch longer than the hardware store fittings. Since the fitting is longer when used with a standard (hardware store) olive the fitting does not bottom out. I tried this nut on a piece of 1/4 inch tubing with a standard hardware store 1/4 inch tubing olive and this was air tight when screwed onto the pump. Installed this arrangement about 2 years ago and no fuel leaks. Picture below is the Moss fitting (376-575) installed with a standard (hardware store) olive.

IMG_0770 (Medium).jpg
 
GeneW said:
Moss 376-575 - This is a tubing nut with a 1/4 inch hole and the nut has longer length versus a standard 1/4 inch tubing nut. At the very end of the nut is an unthreaded section. Measuring from the threaded side of the wrench hex to the end of the fitting, the Moss nut is about 3/32 inch longer than the hardware store fittings. Since the fitting is longer when used with a standard (hardware store) olive the fitting does not bottom out. I tried this nut on a piece of 1/4 inch tubing with a standard hardware store 1/4 inch tubing olive and this was air tight when screwed onto the pump.
Click to expand...

That's actually the solution I used as well, although I made my own extended tip nut (doesn't seem to be in their old printed catalogs). It's worked great for a long time. My only regrets are not making the nut slightly longer than I did, and using brass instead of steel.
 
Last edited:
Although the TRF TR6 catalog lists the tube nut individual part numbers, I was not aware before I talked to Albert that the same tube nuts are used on TR3 through TR6. Randall, that would be great for you to update, with the detail, the TR3 SPC that you make available.

Gene, thanks for that information on the 1/4 inch tube nut. Does the 5/16 tube nut for the input line also have the same "problem" with needing the unthreaded longer piece near the compression fitting? And do you know if Moss sells the 5/16 tube nut separately, and the part number?
Bob
 
TuffTR250 said:
Although the TRF TR6 catalog lists the tube nut individual part numbers, I was not aware before I talked to Albert that the same tube nuts are used on TR3 through TR6. Randall, that would be great for you to update, with the detail, the TR3 SPC that you make available.
Click to expand...
Should be there; let me know if there is a problem. Pages 20 and 60
https://drive.google.com/open?id=0B2H2NJt34OffMWQ4N2EzZGQtNjc0Ny00YmE2LWFiN2UtZWYzMjNjNGFiYzY4

PS, AFAIK, the inlet side does not have the same problem
 
I have a new 1/4" tube nut from TRF. IT is identical to the one in Gene's picture, with the extension below the threads. So it looks like either source provides the same item.
Good to hear that the 5/16" tube nut does not have that same problem. Because neither the old tube nuts nor the new ones have that extension below the threads.
 
Thanks! Good to hear the inlet tube nut does not have the same problem.

Randall, my hardcopy TR2-3 spare parts catalog is version 4 so I can't help with your missing page. I downloaded your latest version attached above. Thanks!
Bob
 
Nice fix for that problem. I do have an original, but I could never get it off the line. Here is a picture of what I am 99.9% sure is original
 

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