Another Ford 801 fuel return line thead

[Jlambert]

Hi All,

I know this issue has been beaten to death but I could still use a few pointers. Working on a Ford 841 diesel and it started getting fuel in the oil. At first it was slow, then it accelerated. I took out the return line fitting from the tank and the small diameter stand pipe fell out loose. The larger and shorter stand pipe is nowhere to be found, (picking up a mirror this afternoon to confirm it's not in the tank).

Does anyone have pictures of how this is supposed to go together? I'm assuming that the line from the injector bleedoff is supposed to be connected to the vertical stand pipe but it's not clear to me how to attach the small pipe down at the bottom of fitting.

Sorry again to bring up an old topic, I did hunt around but couldn't find a diagram.


Thanks!
Joe

 

[super99]

Not familiar with the Ford diesels. Most others have a mechanical fuel pump that will leak diesel fuel into the engine oil as you stated when they go bad. Not sure why you took the fuel return line off or what the stand pipe is for, most just dump into the top of the fuel tank.

 

[used red MN]

Not familiar with the Ford diesels. Most others have a mechanical fuel pump that will leak diesel fuel into the engine oil as you stated when they go bad. Not sure why you took the fuel return line off or what the stand pipe is for, most just dump into the top of the fuel tank.

Don’t worry about bringing repeat topics up in my opinion is why this forum exists. It keeps troubles subjects fresh in our minds. I can’t help you but I understand your problem. If no one answers here take it to the Ford forum.
@super99 I found out about the design of these engines by arguing with someone that the injector return lines cannot leak into the engine. That is not true on these Ford 172 diesels. The injectors and return lines are under the valve cover. CNHI Ford 841 parts catalog Part 61 in this link is the seal for the injector adapter that the injection line connects to sealing it to the opening in the head. A standpipe for the return in the tank keeps the gravity pressure of the fuel from leaking fuel into the engine if a leak develops in the internal return lines.

 

[john in la]

Where is your leak????
In the return line or in the pump???
Fix that leak and your problem will be solved.

A common problem is the metal rail under the valve cover will crack and leak.
Seals 41 and 51 may be leaking but it is usual the metal rail itself.
Part 61 just stops oil from leaking from the motor where the fuel line enters the injector.
It is on the supply side so has nothing to do with the fuel return system.

If you do not see fuel leaking under the valve cover it is very likely the more common problem in the seals of the pump are leaking.
This seal is in the bottom of the injector pump down in the motor so you can not see it leaking.
You just have to assume if the return rail is not leaking it has to be the pump seals.
To fix this you need to have new seals put in the pump.
Just as soon do a rebuild while you have the pump apart.

As far as the stand pipe goes.
There was 2 types.
From your description I can tell what one you have.
The fitting has 2 connection points.
The one on the bottom comes from the fuel rail under the valve cover and hooks to the small tall pipe.
The one on the side comes from the pump and hooks to the short bigger pipe.
These two pipes and the fitting are all one piece soldered together.
This is not something you take apart and put back together.
If the pipes are broke off the part is broke and you need a new one.
I am sure there are guys out there that can solder it back together but its made as a replace it part.

The short bigger pipe does nothing for preventing the fuel tank from flooding the motor with fuel.
It is to short to stop that.
Its only purpose is the stop trash and water from the bottom of the tank from reaching the pump in an unfiltered line.
Like I said if this is your leak you need to rebuild the pump.

The tall small pipe will stop the fuel tank from flooding the motor if your tank is not full and the fuel level is below the top of the pipe.
But every time you start the tractor the return line will fill with fuel.
When you cut off the tractor and fuel in the line will leak into the motor.
So you might slow down the leak but just having a good stand pipe will not stop the leak.
Again fix the source of the leak.

I am on my laptop now.
I will post this and reply to this post with a picture of the stand pipe as I have one on my phone.

 

[john in la]

.

 

[super99]

Don’t worry about bringing repeat topics up in my opinion is why this forum exists. It keeps troubles subjects fresh in our minds. I can’t help you but I understand your problem. If no one answers here take it to the Ford forum.
@super99 I found out about the design of these engines by arguing with someone that the injector return lines cannot leak into the engine. That is not true on these Ford 172 diesels. The injectors and return lines are under the valve cover. CNHI Ford 841 parts catalog Part 61 in this link is the seal for the injector adapter that the injection line connects to sealing it to the opening in the head. A standpipe for the return in the tank keeps the gravity pressure of the fuel from leaking fuel into the engine if a leak develops in the internal return lines.

You learn something new everyday! Luckily I started by saying that I'm not familiar with Ford diesels.

 

[Dieseltech]

The rubber line grommet that seals in the head under the valve cover can fail over time too, that's where the fuel into oil leak was on my 871.

 

[Welding man]

I have fought the fuel in oil problems on dozens of these tractors. Replaced the umbrella seals in the pump-replaced the rubber line grommet in in the head and resoldered the return lines on top of the injectors. It's a process of elimination. Fix one thing. Leave the oil pan drain plug out of the oil pan and let it sit overnight and see what happens. I had to pull the pump on a 4000 SOS yesterday to replace the O-ring on the pump base. Had an oil leak there.

 

[showcrop]

I repaired mine around five years ago. When I removed the fitting from the tank I found that both of the tubes were still there, but the small diam tall one had come unsoldered and with vibration and time had gotten very loose inside the large diam. one. To put it back together I selected a drill bit that almost went into the smaller diam. at the bottom of the large tube and turned it in by hand to clean it up. I then just coated the small tube with JB weld to seal it back together. It has worked so far.

 

[Jlambert]

Thanks all,

On mine the lower pipe is completely missing and the tall pipe was completely loose. I wound up cleaning it and was able to get it re-soldered. Not sure how good a job it was but I was able to lay a bunch of solder on the tube and then heat the fitting so it re-melted the solder when the tube was installed. I'm not super confident but I thought I'd start there before going the JB weld route.

So given that the taller tube was loose is it possible that that was the only thing wrong? I have the pump seal kit here but I'm hesitant to take apart the pump without being sure that's what's wrong. Likewise it looks like the valve cover removal requires taking out the fuel tank which requires taking off all the tin so I was hoping to avoid tearing everything down if not necessary.

Thanks again for the feedback everyone, much appreciated!

 

[moresmoke]

Thanks all,

On mine the lower pipe is completely missing and the tall pipe was completely loose. I wound up cleaning it and was able to get it re-soldered. Not sure how good a job it was but I was able to lay a bunch of solder on the tube and then heat the fitting so it re-melted the solder when the tube was installed. I'm not super confident but I thought I'd start there before going the JB weld route.

So given that the taller tube was loose is it possible that that was the only thing wrong? I have the pump seal kit here but I'm hesitant to take apart the pump without being sure that's what's wrong. Likewise it looks like the valve cover removal requires taking out the fuel tank which requires taking off all the tin so I was hoping to avoid tearing everything down if not necessary.

Thanks again for the feedback everyone, much appreciated!

As John in LA said, fixing the standpipe mitigates the issue, but does not correct it. If the returns are leaking under the valve cover the only fix is to get in there and repair.

Aside from that, if you have never been in the pump, it is worth you time to get seals and a new governor dampener ring installed. It will save you headaches down the road.

 

[M-MAN]

On my 851 there was a couple joints loose on the return pipe under the valve cover. The olive (rubber seal) the pipe fits into was bad also. Found these due to leakage on the side.

Dieseltech rebuilt the pump and I brazed a new standpipe in. Mine is a single standpipe. I suggest you send Dieseltech a pm and let him rebuild the pump. He's reasonable and does quality work.

 

[Jlambert]

Thanks all,

So as I understand the theme here am I correct in my understanding that even with the stand pipe repaired I likely also have a problem either in the pump and/or under the valve covers?

Thanks,

 

[showcrop]

Thanks all,

So as I understand the theme here am I correct in my understanding that even with the stand pipe repaired I likely also have a problem either in the pump and/or under the valve covers?

Thanks,

I agree with that. You don't need to remove the sheet metal to remove the valve cover. It is supposed to roll out to the side. If you find that it is really tight you can loosen the tank mounts and wedge the front up a little higher.