Persistent Fuel Leak - Sediment Bowl Inlet

[Ziggster]

As I inch closer to the actual start-up of my C59A, I added fuel to my lawnmower tank which will be used for cam break-in. As fuel made its way down to the inlet of the sediment bowl, I noticed there was a slight leak (periodic drips). Tried tightening the nut to if that would work, but no difference. Remove the nut and ferrule and notice that the ferrule was just sliding on the tube. Decided to try a new nut and ferrule, and still was leaking. Remove the new nut and new ferrule, and ferrule was still sliding on the tube. I tried to judge how far the tube should protrude into the housing during these attempts. Lastly, I decided to push the tube in as far as it would go and tightened up the nut. Noticed it was better than before (no periodic drips), but the nut still was getting “wet” with fuel. Any idea what is going on? I only have two new ferrules left and don’t want to ruin any more trying to fix this leak.

[hueyhoolihan]

BTDT

i was having the same problem with my fuel line from tank to fuel pump. and ended up switching from a compression fitting to a barbed fitting with flexible hose and clamp. ...and then...

i had a similar problem with the hard fuel line from the pump to the carb. both ends were compression fittings. one end would not leak and the other end would leak no matter what i tried. i eventually turned the fuel line end for end, re-bent it to fit, and then re-attached it. ... that fixed it.

i suspect there are compression fittings out there with threaded male connectors with different lengths from the beginning of the threads to their shoulders. and/or female connectors with different lengths from flare to where the male connector's shoulder sits. but it's just a suspicion.

and of course, there is always the possibility of ruining everything by stripping out the aluminum housing of a pump or carb. so, one can't really put the kind of hurt on it one might like to.

BTW, if a ferrule is still sliding on the tube after a compression fitting is tightened, then it has probably not been tightened sufficiently, IME. not that tightening further would necessarily fix the problem or prevent ruination. again...IME.

[Ziggster]

Yeah, I’ve tightened it as far as I dare. Will remove and see if the ferrule still slides.

[petehoovie]

Originally Posted by Ziggster

As I inch closer to the actual start-up of my C59A, I added fuel to my lawnmower tank which will be used for cam break-in. As fuel made its way down to the inlet of the sediment bowl, I noticed there was a slight leak (periodic drips). Tried tightening the nut to if that would work, but no difference. Remove the nut and ferrule and notice that the ferrule was just sliding on the tube. Decided to try a new nut and ferrule, and still was leaking. Remove the new nut and new ferrule, and ferrule was still sliding on the tube. I tried to judge how far the tube should protrude into the housing during these attempts. Lastly, I decided to push the tube in as far as it would go and tightened up the nut. Noticed it was better than before (no periodic drips), but the nut still was getting “wet” with fuel. Any idea what is going on? I only have two new ferrules left and don’t want to ruin any more trying to fix this leak.

[Kens 36]

Ziggster,

I may be confused about what I think I see in the picture. Is that a solid line coming up the firewall from the fuel tank? If so, this would be very dangerous as the engine moves and a flex line is required.

Maybe I'm just seeing it wrong.

Ken

[kurt v]

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you need the rubber fuel line with the correct fittings as stated by KEN.

[Bob C]

Solder the ferrule to the fuel line.

[Steve51]

As two others have stated, you need a hose barb fitting on the fuel pump to a short length of rubber fuel line then connected to the metal fuel line.

[Scott52]

Are you sure the female end where the tubing goes in isn't just a pipe thread? I have several generic fuel filters that are that way. They need a brass male pipe thread to Compression or flare fitting. These are not Fords. My Ford fuel pump has a barbed fitting for a flex gas line and a pipe thread on the other end while it is in the engine test stand.

[Bob C]

Check out what the male end of the flex hose looks like.

[Ziggster]

Originally Posted by Kens 36

Ziggster,

I may be confused about what I think I see in the picture. Is that a solid line coming up the firewall from the fuel tank? If so, this would be very dangerous as the engine moves and a flex line is required.

Maybe I'm just seeing it wrong.

Ken

Yes, but it joins a short section of hose that goes to an in-line fuel filter. This whole set-up is a mock up. This is just going to be used to break-in the cam for 20 mins.
For sure in the future and in the final configuration, there will be a good length of hose. Maybe, I shouldn’t have used the word “persistent” as folks could think this was a long term issue. Haha!
The issue came about just as I added fuel in preparation for the first start-up since I started construction of my speedster back in 2018.

[Ziggster]

Still weeping a bit (nut is wet from fuel). There is also some fuel on the bottom of the fuel sediment bowl. Fuel is also weeping out a bit from the fuel pump diaphragm joint. I’ve read that there are folks who do not like the Ford stk sediment bowl because of how it leaks.

[Ziggster]

Pic of the fuel line(s) to the tank.

[Ziggster]

Wetting of fuel pump diaphragm joint.

[Mart]

I'd be looking carefully at the surfaces of the seat and the ferrule. I'd also be looking at the stack up of the pieces. Is the nut bottoming before crushing the ferrule? Why is it not crimping the ferrule to the pipe? Is it 1/4" pipe? Are the ferrules 1/4"? The only time I have not had one seal was when the nut was bottoming against the housing before crimping the ferrule. Is it a separate ferrule or one of those where it is built into the nut?

Keep looking.

The pump might leak like that at the diaphragm because it is dry. You have a gravity feed going. The pump is not normally pressurised like that. It ought to stop after being exposed to fuel for a while. That might be what is happening at the ferrule, but I'd be surprised. Try lowering the tank so the pump is pulling the fuel uphill.

It must be very close to firing. Good luck with it.

Mart.

[Ziggster]

Thanks Matt. I’ve already buggered 3 ferrules on the two other ports (fuel pump outlet & carb inlet). The ferrules are separate, and both the ferrules and nuts are new. I think I got them from 3rd Gen as well as the fuel line. I find the issue for me (or at least one of them), is understanding how far the fuel line should protrude into each of the ports.

[Ziggster]

Originally Posted by Scott52

Are you sure the female end where the tubing goes in isn't just a pipe thread? I have several generic fuel filters that are that way. They need a brass male pipe thread to Compression or flare fitting. These are not Fords. My Ford fuel pump has a barbed fitting for a flex gas line and a pipe thread on the other end while it is in the engine test stand.

Not sure. It’s the intake and fuel pump assy that came with the engine. Maybe someone tried a pipe thread fitting at some point.

[cas3]

look inside, if its got the cone shape to crush the ferrel its a Ford nut with ferrel. If no cone shape, it could be pipe thread

[Ziggster]

Previously buggered ferrules.

[Ziggster]

Nut/ferrule from sediment bowl inlet (original attempt). The ferrule still slides over the 1/4” tube with no issues. Almost feels too loose. What would cause this to happen?