Morgan Wright Posted September 13, 2022 Share Posted September 13, 2022 I think most of us with teens and 20's Buicks have this problem, gas dripping slowly in this line, so we have to turn off the gas at the vacuum tank every time we turn off the car, to avoid a puddle of gasoline on the floor and exhaust pipe. You just learn to live with it. I tried to tighten the nut at the carb end of the line to stop the leak, but tightening it just made it worse, I saw the fitting was soldered, no way to tighten it!! So I took the line off, melted the solder, moved it over a little, resoldered it, put it back, now the leak is at the vacuum tank end of the line. Tried to tighten that end, impossible to stop the leak. It's a compression fit which requires soft copper, but the line in these old cars is antique copper which is an impure alloy, not soft copper, and compression fittings simply don't work on this old hard "copper". To fix it, need to replace the copper tube with modern soft copper. But, can't find 5/16 inch copper tube anywhere, the size is not used by plumbers anymore. Luckily it's a size use by AC people. I have to buy many fittings. Flare fitting on one end to replace the stupid soldered fitting, compression fitting on the other. To make it affordable I'm buying 6 of everything so maybe other people with this problem can chip in. 3 Link to comment Share on other sites More sharing options...
Oldtech Posted September 13, 2022 Share Posted September 13, 2022 Strangely or maybe not, my McLaughlin has all brass lines. Link to comment Share on other sites More sharing options...
Bloo Posted September 13, 2022 Share Posted September 13, 2022 Soft copper isn't soft for long. Copper gets hard right away when you bend it. Heat it to red to anneal it. More than once if necessary.. It's hard to tell from that mangled tube what it is supposed to look like. If you need to make tighter bends, start out with a longer piece of tubing, pack it with sand, crimp and roll up the ends so the sand is tight, and make your bends ahead of time then cut your "new part" out of the middle. The soldered 1/4" pipe fitting (looks like 1/8" in the picture?) can easily be salvaged and resoldered. Is the other end a ferrule? If you can't get 5/16" tubing and ferrules (if needed?) locally, maybe online? I got some 5/16" copper at a local hardware store to make fuel pickup tubes for 1930s GM fuel sending units, although it does seem uncommon. The big chains don't have it. If you think the copper might be too hard to work with a ferrule, anneal the end one more time before you put it together. 4 Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 13, 2022 Author Share Posted September 13, 2022 Yeah it looks like it used to be a ferrule. Can't say what it is now, in mixed company. Link to comment Share on other sites More sharing options...
EmTee Posted September 13, 2022 Share Posted September 13, 2022 3 hours ago, Morgan Wright said: Yeah it looks like it used to be a ferrule. Can't say what it is now, in mixed company. Do you think that forming a 'bubble' at the end of the tube using your double-flare tool could work instead of the (missing) ferrule? Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 13, 2022 Author Share Posted September 13, 2022 (edited) 18 hours ago, Bloo said: The soldered 1/4" pipe fitting (looks like 1/8" in the picture?) can easi Yeah it's 1/8 inch.I'm adding the flare joint to the carburetor end and getting rid of the stupid solder joint. It will make that end of the line removable and tighten-able. Still waiting on the 5/16 tube but this is what I have so far...... a 5/16 flare to 1/8 pipe thread adapter for one end, and the 5/16 compression fitting will work in place of the ferrule for the other end: Edited September 13, 2022 by Morgan Wright (see edit history) 2 Link to comment Share on other sites More sharing options...
DonMicheletti Posted September 13, 2022 Share Posted September 13, 2022 I had the exact same problems. All the original fuel lines on my car are brass too. This was my successfull fix. I took the "stupid soldered joint" apart, cleaned the tube and ID of the fitting and resoldered it with soft solder. On the ferrule end, I worked on the tube behind the nut and was able to back the nut away from the ferrule (which was loose on the tube rotationally). I cleaned the tube and ferrule very carefully and soft soldered the two together and also "wiped" the ferrule with solder (photo). It isnt pretty, but it worked. When assembled, no more leaks. In "wiping" the ferrule with soft solder, the solder on the ferrule crushes to match the tank fitting on assembly. It took me about an hour, I spent 0$ and it is still all original and non leaking. 8 1 Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 14, 2022 Author Share Posted September 14, 2022 I admire your desire to keep everything original, but the ferrule end of my line is not round. No amount of careful cleaning will make it round again. Some idioot in the past (me 2 years ago, and again last week) mangled that line, and because it's brass and not soft copper, it will never see anything close to round again. My bad. 1 Link to comment Share on other sites More sharing options...
Terry Wiegand Posted September 14, 2022 Share Posted September 14, 2022 When I was setting the engine together for my '16, when I got to the intake manifold with the vacuum tank in place and the carburetor installed, I used soft copper for the connecting fuel line. If my memory is correct, both ends of the line were flared. I'll post a photo of the extra shutoff valve that I have that is on the bottom of the vacuum tank. I have had absolutely no problems with the connections seeping or leaking. I always shut the fuel valve off on the bottom of the vacuum tank when the engine is not running to keep the pressure off the needle and seat and cut the chances down of any leakage at that point. I am familiar with tube bending and how to do it without kinks and deforming the line. The external oil lines on this engine are a different story. They are brass and relatively heavy gauge for their intended purpose. Terry Wiegand South Hutchinson, Kansas AACA Life Member #947918 3 Link to comment Share on other sites More sharing options...
Bloo Posted September 14, 2022 Share Posted September 14, 2022 For what it's worth, you can anneal brass the same way you do copper, heat it to red. You can quench it if you like, or not, it makes no difference. It gets pretty soft and floppy until you bend it some more, but it work hardens fast. No matter, that is going to need a piece of new tubing whether it is copper or brass. Another possibility is CuNiFer/Nicopp, not available in the 20s, but it looks like copper and is allegedly not prone to cracking like copper and brass are. 3 Link to comment Share on other sites More sharing options...
DonMicheletti Posted September 14, 2022 Share Posted September 14, 2022 Morgan, my biggest challenge on that repair was to get the tube round enough to back the nut off enough to do the job. Yours is a lot worse than mine was Link to comment Share on other sites More sharing options...
Terry Wiegand Posted September 14, 2022 Share Posted September 14, 2022 Here is a photo of the fuel shutoff fitting like the one on the bottom of the vacuum tank on my '16. The male threaded end goes into the bottom of the tank and a 90 degree elbow goes into the bottom of the fitting. As I stated earlier, I have not had any problems with fuel seepage and/or leakage with the fittings on this end or the float bowl end of this line. I was very careful while putting things together and so far everything has worked just fine. That's my story and I cannot add a thing to what I did. The elbow does away with a bend in the line. Terry Wiegand South Hutchinson, Kansas AACA Life Member #947918 1 Link to comment Share on other sites More sharing options...
DonMicheletti Posted September 14, 2022 Share Posted September 14, 2022 The '18 has a different valve. 1/4 turn shutoff. It is a special valve, probably Stewart. Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 15, 2022 Author Share Posted September 15, 2022 My leak was from the solder joint, and when I removed the line to re-solder it, the bend to the vacuum tank was 180 degrees off from where it needed to be, so I had to bend the whole tube. The tube is brass, so I had to put it in a vice and bend it with a long lever, which just mangled it. (I should have just melted the solder, turned the nipple 180 degrees, and re-soldered it.) Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 15, 2022 Author Share Posted September 15, 2022 And here we are boys and girls. All flared and ferruled and ready to go. I had to cut the old ferrule off as you can see. 3 Link to comment Share on other sites More sharing options...
DonMicheletti Posted September 16, 2022 Share Posted September 16, 2022 Why does hindsight come so late in the game? Link to comment Share on other sites More sharing options...
EmTee Posted September 17, 2022 Share Posted September 17, 2022 My hindsight used to be 20/20. Now it requires bifocals... 1 Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 17, 2022 Author Share Posted September 17, 2022 My hindsight was good enough to see that I should have twisted the nipple 180 degrees and resolder, but my 20/20 foresight tells me that to prevent the problem in the future, get rid of the solder joint completely. Now I can remove the carburetor as many times as I want without messing with the fuel line. Just loosen the nut and bingo, the carburetor falls off in your hand like M & M's 1 Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 17, 2022 Author Share Posted September 17, 2022 I pre-bent the line around a small saucepan with a suitable radius of curvature. 4 Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 17, 2022 Author Share Posted September 17, 2022 (edited) FAIL!! The flare nut bumps into the bottom of the carb bowl and doesn't fit. Edited September 18, 2022 by Morgan Wright (see edit history) Link to comment Share on other sites More sharing options...
Morgan Wright Posted September 17, 2022 Author Share Posted September 17, 2022 I had to remove everything and resolder the joint like it originally was so it would fit. Isn't it pretty? Link to comment Share on other sites More sharing options...
Oldtech Posted September 17, 2022 Share Posted September 17, 2022 AARG! 1 1 Link to comment Share on other sites More sharing options...
EmTee Posted September 17, 2022 Share Posted September 17, 2022 I hate when that happens... https://www.youtube.com/watch?v=G8vRM4wPcBk 1 Link to comment Share on other sites More sharing options...
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