Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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. :)

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Solder the ferrule to the fuel line.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Wetting of fuel pump diaphragm joint.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Previously buggered ferrules.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

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?

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Fuel level in filter. Not sure why it’s only half fuel, but somehow fuel must be tricking down to the sediment bowl inlet. The tank is almost full.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Earlier this afternoon, I gave a “tug” on the fuel
line going into the sediment bowl inlet. It was a sideways pull because I was wondering if the tube was slightly off-axis to the inlet port. A couple hrs later, and it’s not weeping! Completely dry. Didn’t touch the nut. WTH!?

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Those are the ferrules that are part of the nut. Not the best. (in my opinion). Go to a good hardware store or ebay and get some 1/4" ferrules (we call them olives over here).
They will work with those nuts but proper ford nuts are better. Napa might have them. can't remember the number.

Glad you did get it to seal though. If done correctly they ought to be reusable multiple times.

Mart.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Sorry Mart, I should have made it clear in that pic, but the ferrule was loose, it’s now just stuck to the nut. I do agree though about your statement, as I recall someone mentioning that previously to me when I was looking for the nuts/ferrules, and that’s why I went with the loose ones.

Joint is still dry. I just cannot believe that a tug on the line solved the issue. We’ll see if it lasts today, as the plan is to fire up the engine for the very first time.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Still weeping. So, removed line. Ferrule now stuck to tube, but looking at the seat area of the housing it looks flat to me. As folks have suggested, I should have checked this out first. What do you guys think?

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

https://www.fordbarn.com/forum/attac...0&d=1758133045

https://www.fordbarn.com/forum/attac...1&d=1758133045

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Checked the fuel pump from my other flathead. It had this fitting in it. It’s flared at both ends, and has a 3/16” OD hole thru it. I would need a female flare nut, and would have to flare the end of my 1/4” tube. Threads into my hsg. Looking at the seat area it looks like there might be a bit of an inverted flare area similar to the one in the other hsg.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

ferrules once tightened sufficiently are compressed and are generally not removable from the tube. if they were the connection would leak.

this AI definition is pretty a good definition of a flared compression fitting involving the use of a ferrule...

A compression flared fitting with an olive (or ferrule) is a plumbing component used to create a watertight, airtight seal on tubing, typically copper or plastic. The fitting consists of a nut, the compression ring (olive/ferrule), and the fitting body. When the nut is tightened, it compresses the olive onto the tube, creating the secure connection needed for high-pressure applications in plumbing, pneumatic, and hydraulic systems

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

https://www.fordbarn.com/forum/attac...3&d=1758134236

https://www.fordbarn.com/forum/attac...4&d=1758134236

https://www.fordbarn.com/forum/attac...5&d=1758134236

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

You don't by chance have a later (8BA) fuel pump do you? In late '51 Ford changed from a "Ford Nut" on the fuel pump inlet to a pipe thread that needed a fitting. This has caused a lot of confusion and problems over the years.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

No, unfortunately. Thought this would be easy peasy, so headed back into town. CarQuest had nothing. Same with big box store, as well as a large plumbing store. Note sure of the size, but guy at plumbing store said it was bigger than 1/4” flare fitting, and too small for a 3/8” flare fitting. Said it was probably a 5/16” size (-5).
I recall now all the threads I read a while back about the confusion with these Ford fuel fittings. Oh vey…!

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Those threads look kinda "iffy to me; probably caused by someone trying to force something in the past. If there's enough meat, drill it and tap it to the next larger NPT. Then get an appropriate brass fitting to what ever you need.

Plan "B" is a new pump.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Brass threads are good on the fitting I removed from the “second” fuel pump assy. Not sure as to the female threads on that fuel pump assy. The threads on my fuel pump assy are fine.
Speaking of threads, the size/pitch of the female thread at the sediment bowl inlet is 1/2”-20. The brass fitting from the second fuel pump assy has the correct size/pitch (1/2”-20). The 45 degree flare on the brass fitting is for a 1/4” OD tube. The “issue” is that according to the size chart in the pic, the 1/2”-20 thread is for a dash 5 (-5) fitting size which is for a 5/16” OD tube.
I’ll McGuyver something up, and post when done.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Are you sure about the inlet being "1/2-20"? That sounds like NPT and seems a bit large for a fuel fitting. Pipe sizes are the inside diameter of the pipe, while tubing sizes are outside diameter; quite a difference.

I think I may have a problem with communication here.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Fuel line should be coated steel ,But i use copper ,set the feral /olive on a brass seat such as a Stromberg inlet fitting or the female end of your flex line not in the pump .diaphragm
matting surface should be sanded on a flat surface , thick cork or rubber for the boil

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

The flexible rubber fuel hose is the CORRECT line going into the fuel pump from the steel line coming from the tank - see Bob C.'s post #10 above. It would be advisable to use the proper part there. It's not worth risking a potential fire trying to make something else work.

https://thirdgenauto.com/product/193...-to-pump-hose/

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Went through the stash of parts from my second flathead. Found another fitting similar to the one posted, but this one has NPT at the other end! Problem solved assuming the 45 degree or whatever that angle is seals against the hsg. I’ll get a hose barb fitting and attach it, and run hose to the filter.

Re: Persistent Fuel Leak - Sediment Bowl Inlet
 

Also found the original fuel line from the pump to carb from the second flathead. It has the nuts and ferrules on it like mine, and one of the ferrules is at the edge of the tube, so I don’t feel too bad. lol!