Gas line leak

B

Bob Leonard

Junior Member
I'm (still) trying to get my 1931 Deluxe Roadster back on the road, and every time I think I'm ready to crank it up, something else happens.

I put a new sediment bowl assembly on it and hooked up the fuel line in the car. When I put gas in the tank, I noticed that the line was leaking where it met the assembly. It's not just an occasional drip but a full-fledged streaming leak. I bought a new line to go from the valve to the sediment bowl assembly, but the new one leaks, too. Everything at the point of the leak is now brand new.

I am sure that it is screwed on tight enough.

Am I doing something wrong? What should I try next?

This is the only thing that stands in the way of my cranking it.

P.S. While I'm at it, should I put oil, or something else, in the cylinder to ensure that the first crank after 10 years is fully protected until I get good oil circulation

Thanks for any advice.
 
A little oil in the cylinders before startup might be a good idea. On the leaks look for craks in everything, and consider thread sealant at joints.
 
I had a similar issue with my 29 at startup in late December after the rebuilt engine was installed. The ferrule on the line that went into the sediment bowl had got cracked when I tightened it up during the install. Replacing the ferrule was all it needed to stop the leak.
The other thing that can get you here is there needs to be something like 1/8” of fuel line that sticks out past the end of the ferrule as you tighten it up. The way I do it is to take a fine point sharpie and make an ink mark on the line with the ferrule in the right place before installation, then tighten things up making sure the mark stays in the right location. This ensures the 1/8 is held, and the sharpie can be easily removed after you are done.
Good luck with the leak.
 
The repop sediment bowls are really crappy, and it's very easy to get the gas line from the tank cross-threaded onto the inlet and not notice it. Once that happens and you tighten it down, you're pretty much screwed as the pot metal of the sediment bowl assembly is so soft that you'll never get it back correct. If you can find an original sediment bowl assembly (try Steve Becker at Bert's Model A Store?) much better, otherwise you may have to just get another new one and very carefully thread on that fitting.
 
Bob Leonard said:
I'm (still) trying to get my 1931 Deluxe Roadster back on the road, and every time I think I'm ready to crank it up, something else happens.

I put a new sediment bowl assembly on it and hooked up the fuel line in the car. When I put gas in the tank, I noticed that the line was leaking where it met the assembly. It's not just an occasional drip but a full-fledged streaming leak. I bought a new line to go from the valve to the sediment bowl assembly, but the new one leaks, too. Everything at the point of the leak is now brand new.

I am sure that it is screwed on tight enough.

Am I doing something wrong? What should I try next?

This is the only thing that stands in the way of my cranking it.

P.S. While I'm at it, should I put oil, or something else, in the cylinder to ensure that the first crank after 10 years is fully protected until I get good oil circulation

Thanks for any advice.
Click to expand...

sounds like you are almost there! :)

if anything can leak, surely gasoline is one of the best to do just that! give it an inch....

Am I doing something wrong? What should I try next?

maybe post up some pix of your components. up close shots inlets, etc

if you have to buy new again, wash clean first and try a vac test on assembled components. line to bowl in, line to bowl out. then get it into some water and try a blow thru... if all high n dry, assemble in same fashion. pipes like teflon, ferrules like compression.

maybe a blow thru can show you point of leakage
 
FYI, Snyder’s has oversize ferrules if everything looks OK and you still can’t get it to seal. Sometimes the fitting bottoms out on the sediment bowl or carburetor and does not tighten on the ferrule.

I think most vendors are out of stock on the Sediment Bowls.
 
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Keep in mind that the "ring" (ferrule?) has to "indent" the line to make a proper seal. The two sides of the ring are "tapered" to a feather edge and when put on properly with the nut, the ring cannot be removed afterwards. Frequently captivates the compression nut too requiring cutting the line to recover the nut.

Compression fittings tend to be a "one time only" fitting - except once established as tight they frequently re-set as tight.

The flare is similar except here you do get a chance to use the flare tool to "reform the flare." That is providing you can get the tool on straight. I have used a grinder to grind off perhaps 20 percent of the flare, and then re-set the tool and reform "deeper."

I have also "given up" on the flare as the seal mechanism, and put a thin rubber washer in the interstice.

Joe K
 
WOW!!! Five responses in nine hours. Noe, that's impressive.

It looks like I need to take out the sediment bowl assembly and work with the gas line on my workbench to see if there are any cracks or if there is a misthread. Also, I have the old (possibly original) sediment bowl assembly, and I'll see if the glass bowl that I got with the new one fits. If so, then that is what is going back on. If not, then if the threads are buggered up, I guess I'll have to get a new assembly.

The test is a good idea. I don't know what equipment I would need for a "vac test," but I can surely try to blow water through the entire thing.

I'll report back on what I find next weekend.

Also, regarding the issue of oil in the cylinders, I have heard people suggest Marvel Mystery Oil because it is thinner and can better get down into the rings, etc. Does that make sense? Is there anything besides oil or MMO that would make sense? I'd hate to work so hard to get back on the road and then ruin my engine.

Again, thanks a lot for the quick responses.
 
Joe K said:
The flare is similar except here you do get a chance to use the flare tool to "reform the flare." That is providing you can get the tool on straight. I have used a grinder to grind off perhaps 20 percent of the flare, and then re-set the tool and reform "deeper."

I have also "given up" on the flare as the seal mechanism, and put a thin rubber washer in the interstice.

Joe K
Click to expand...

Joe, I had to resort to using a "Flare Fitting Gasket" to get my inside fuel line the seal against my Sediment Bowl. Made of copper, probably a better option than using a rubber washer on a fuel line inside the car.

561820


https://www.amazon.com/dp/B074P5KP8Z?tag=atomicindus08-20
 

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I would not use MMO for that. Use a good amount of oil and let it sit for a few nights before you start it. That will coat everything much better than MMO.

I use 4oz of MMO with every tank fill-up.
 
There are two flaring angles. 37 degree and 45. 37 is generally for aircraft???? 45 for automotive, the appropriate nuts for each needs to be used. You might check that. If your new sediment bowl is 45 and the A is 37, or vice versa, this could be the issue. Measure the angles by drawing lines on paper???? Did you buy the bowl from a model A vendor? Your new bowl could be for a tractor????

I'm not sure, but I think the Model a line from the shutoff to the sediment bowl is actually a 37 degree but Im not sure that I am correct. Others need to verify this as its long term memory at this point???????????????????
 
Back to oil in the cylinders. Pull the distributor and pour a quart down the hole. That puts new oil in the valve body and feeds the mains. Pull the oil plug and check the flow when cranking the first time.
 
The sediment bowl assembly is cast pot metal and it is really easy to screw up the threads. A little Permatex 2 helps. It does not dissolve in gasoline like the silicone gasket cements do.
 
I screwed up the threads on a new sediment bowl assembly completely ruining it, so don’t take my advice! It’s really easy to cross thread the line from the cut off valve to the back of the sediment bowl inside the cab.

I suggest that when you reinstall the sediment bowl assembly, do not tighten it to the firewall. Just thread the nut on far enough to hold it in the firewall. That will make it easier to manipulate the bowl and the fuel line to get the line started onto the threads without cross threading. After you have tightened the line finger tight, you can snug up the sediment bowl to the firewall. It worked for me.

W. Michael
 
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