Pigtail overflow pipe leaking excessively.

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leeroy
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Pigtail overflow pipe leaking excessively.

Post by leeroy »

This is on Hyacinth, our '54 FMD.
I started her up and moved her out of barn to warm up. When I got off I noticed a stream of fuel coming from that overflow pipe.
A steady enough stream that had me questioning why she did not starve for fuel.
I backed her back into the barn with no issue, but am very concerned and would appreciate advice.

Could the excess fuel control be the culprit? Interestingly I chose not to use it on that start as we are 5c- fairly warm, and she started fine.
To be clear this is the external pipe on the bottom/front of fuel injection pump just above oil filer. Vacuum governor.
1939 Ford 9N, 1952 8N, 1955 FMD, IH 340U, Ford 3600, Ford 2120, Valmet 646 Forwarder.

John b
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Re: Pigtail overflow pipe leaking excessively.

Post by John b »

Does your pump have a lift pump on the side of it?
My biggest fear is that when i die my wife will sell my tractors for what i told her they cost

Billy26F5
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Re: Pigtail overflow pipe leaking excessively.

Post by Billy26F5 »

It seems there's a fuel leak in the injector pump, you would only notice it if it was a leaking plunger, it doesn't sound like it from what you say. The lift pump gives a high fuel flow to the injector pump, so the leak has to be considerable to get fuel starvation. I recommend you look in the inspection cover on the injector pump, but you will need to ensure no dirt can get in before you do this, you'll want to have a short run to see if you can find the leak, I would be careful of fuel spray just in case. I wouldn't expect the excess fuel position to be too relevant in this but a wee look should make it clearer. Good point John, although I think I'm right in saying that Hyacinth has the std. fuel system rather than the exhauster fitted version.
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leeroy
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Re: Pigtail overflow pipe leaking excessively.

Post by leeroy »

Hello guys, thanks for the fast responses!
John b- no, the lift pump is not on the pump itself, but on the engine block below the fuel filter.
Sandy-I,ll take a close look at excess fuel control and then move on to the inspection cover.

Two other things I forgot to mention:
1- bleed screw on injector pump has started to leak worse than it was. New screw and copper washer should be here soon.
2- I did check all fasteners on pump recently, including the banjo bolt on that leak off pipe.
1939 Ford 9N, 1952 8N, 1955 FMD, IH 340U, Ford 3600, Ford 2120, Valmet 646 Forwarder.

John b
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Re: Pigtail overflow pipe leaking excessively.

Post by John b »

Thats a shame, the lift pump is usually the culprit when they are on the injector pump. You'll have to do as Sandy says, remove the side plate and see if you can see an obvious problem
My biggest fear is that when i die my wife will sell my tractors for what i told her they cost

Billy26F5
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Re: Pigtail overflow pipe leaking excessively.

Post by Billy26F5 »

leeroy wrote:
Wed Mar 02, 2022 10:13 pm
bleed screw on injector pump has started to leak worse than it was. New screw and copper washer should be here soon.
You should only need the washer, but the screw should help too. Do remember to ensure no dirt can get into the pump.
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shepp
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Re: Pigtail overflow pipe leaking excessively.

Post by shepp »

It seems unlikely that such a large flow of fuel could be from fuel getting past the pump plungers and barrels, as a pump worn that much would be unable to deliver fuel at sufficient pressure to open the injectors. If you remove the 8/4 bolt cover plate and start the engine you might be able to see what is going on. The delivery valve holders in the top of the pump body ( onto which the injector pipes are screwed ) have sealing washers underneath them which could have failed, or the holders themselves could be loose on the threads where they screw into the top of the pump body. They often become loose when injector pipes are loosened at the pump end.

Another thing to look out for, especially if you have had issues with leakage from the bleed screw area, is a crack in the pump body casing caused by over tightening of the bleed screw, allowing fuel from the internal charge chamber to spew into the pump cambox under pressure from the lift pump as well as to leak to the outside. You might be able to see that with the side cover off.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

leeroy
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Re: Pigtail overflow pipe leaking excessively.

Post by leeroy »

Thanks for the replies.
The excess fuel control is working correctly.
I need to get to the Ford 8N so I started Hyacinth to move her quick. No leak at all?!
I did the work I needed to do with the 8N, pulled it in, then started Hyacinth up to pull her back in-again-no leaks.
The only other thing I thought of is this: I habitually prime the lift pump by hand lever before first start of the day.
I do recall noticing a longer stroke and pressure than usual.
I'll keep you updated of any changes.
1939 Ford 9N, 1952 8N, 1955 FMD, IH 340U, Ford 3600, Ford 2120, Valmet 646 Forwarder.

Billy26F5
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Re: Pigtail overflow pipe leaking excessively.

Post by Billy26F5 »

If it has sorted itself out that would be great, but keep an eye on it just in case.
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leeroy
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Re: Pigtail overflow pipe leaking excessively.

Post by leeroy »

shepp wrote:
Wed Mar 02, 2022 10:50 pm

Another thing to look out for, especially if you have had issues with leakage from the bleed screw area, is a crack in the pump body casing caused by over tightening of the bleed screw, allowing fuel from the internal charge chamber to spew into the pump cambox under pressure from the lift pump as well as to leak to the outside. You might be able to see that with the side cover off.
Thanks Shepp. Hope this is not the problem but the bleed screw is pretty chewed up, so likely has been over tightened in past.
1939 Ford 9N, 1952 8N, 1955 FMD, IH 340U, Ford 3600, Ford 2120, Valmet 646 Forwarder.

Billy26F5
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Re: Pigtail overflow pipe leaking excessively.

Post by Billy26F5 »

An overtightened bleed screw is also likely to pop off sheared, so you're quite lucky in that sense; hope the new bits sort everything.
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leeroy
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Re: Pigtail overflow pipe leaking excessively.

Post by leeroy »

I've got a theory that is probably not the answer, but have to mention it:
The day I pulled Hyacinth out of the barn I left her running parked on an incline. Her left side higher than her right side.
Could this have caused the leak? I thought of this yesterday when I was pulling her out of the way again.
I did not leave her tipped when the idea stuck, so it's just a theory. She has not leaked since, but only quick runs to move her out of the way.
Still waiting on new bleed screw and washer.
1939 Ford 9N, 1952 8N, 1955 FMD, IH 340U, Ford 3600, Ford 2120, Valmet 646 Forwarder.

Billy26F5
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Re: Pigtail overflow pipe leaking excessively.

Post by Billy26F5 »

As you say, quick runs are not much indication, but what you say does sound possible. Good luck with the bleed screw!
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shepp
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Re: Pigtail overflow pipe leaking excessively.

Post by shepp »

It is possible that having the engine running whilst having the tractor tilted with the left side higher than the right side might have produced the original flush of fuel from the pigtail drain off pipe, especially if the tractor has been run on an even keel for some time. In normal running a small amount of fuel will leak past between the plungers and barrels of the pumping elements and drop into the pump cambox. The pigtail drain off is there to keep the fluid level constant to the level of the pigtail banjo bolt and to drain off this fuel that leaks down. It is normal for a small amount of diesel to leak past the pumping elements even on a pump in good order. When the pump is new or has just been reconditioned it is initially filled with engine oil to the level of the leak off pipe banjo bolt. After that the pump relies on the diesel leak off to keep the fluid level up to scratch and the handbook does not specify a procedure to check or maintain the lubricant levels in the pump cambox as it is expected that diesel leak off will do that. It was only when the minimec pump was introduced in 1962 that a service procedure was specified for the injection pump lubrication as that pump has a drain off plug, a level plug and a fill plug, the vacuum governed pump has none of these just the leak off pipe. If there is no more leakage of material amounts of fuel from the pigtail during normal running then I think you have identified what happened and there should be nothing to worry about.
1946 E27N, 1952 Major Diesel, 1959 Power Major, 1962 Dexta, 1962 Super Dexta, 1963 Super Dexta NP, 1964 Super Major NP, 1965 Super Dexta 3000, 1966 Major 4000, 1967 3000 PF, 1994 5640,plus Basildon built NH.

Billy26F5
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Re: Pigtail overflow pipe leaking excessively.

Post by Billy26F5 »

shepp wrote:
Tue Mar 08, 2022 9:55 pm
It is possible that having the engine running whilst having the tractor tilted with the left side higher than the right side might have produced the original flush of fuel from the pigtail drain off pipe, especially if the tractor has been run on an even keel for some time. In normal running a small amount of fuel will leak past between the plungers and barrels of the pumping elements and drop into the pump cambox. The pigtail drain off is there to keep the fluid level constant to the level of the pigtail banjo bolt and to drain off this fuel that leaks down. It is normal for a small amount of diesel to leak past the pumping elements even on a pump in good order. When the pump is new or has just been reconditioned it is initially filled with engine oil to the level of the leak off pipe banjo bolt. After that the pump relies on the diesel leak off to keep the fluid level up to scratch and the handbook does not specify a procedure to check or maintain the lubricant levels in the pump cambox as it is expected that diesel leak off will do that. It was only when the minimec pump was introduced in 1962 that a service procedure was specified for the injection pump lubrication as that pump has a drain off plug, a level plug and a fill plug, the vacuum governed pump has none of these just the leak off pipe. If there is no more leakage of material amounts of fuel from the pigtail during normal running then I think you have identified what happened and there should be nothing to worry about.
Agree 100%.
Sandy
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