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Fuel Leak Injecter Pump Area - M35A2

TheRecorder

TheRecorder

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1972 AM General with a Continental engine has a developing leak from the injection pump I believe. At least that is where I can see it leaking from. I am going to try to add a photo that displays the system diagram. The leak is comming from right underneath the round component (highlighted green), where the six injector lines come into.
Does anyone have knowledge of the seals needed and where I can buy them?

Thank You
 

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U

unclemikey

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My truck is down right now for the very same reason. Get your face down by the Hydraulic head of the F. I system with a flashlight and have someone crank the engine over WITHOUT STARTING ! You should see the fuel leak if it is coming from under the head or from the side of the head. In my case, there was a very very small hairline crack right on the side of the hydraulic head. Hard to believe, but there it was. When running it could never be seen, but when under starter was easy to find. Best of luck, hope it is just the o-ring under the head, if not, R & R time. Good Luck !
 
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doghead

doghead

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unclemikey said:
My truck is down right now for the very same reason. Get your face down by the Hydraulic head of the F. I system with a flashlight and have someone crank the engine over WITHOUT STARTING ! You should see the fuel leak if it is coming from under the head or from the side of the head. In my case, there was a very very small hairline crack right on the side of the hydraulic head. Hard to believe, but there it was. When running it could never be seen, but when under starter was easy to find. Best of luck, hope it is just the o-ring under the head, if not, R & R time. Good Luck !
Click to expand...


Be sure to wear eye protection, anytime you are looking at the fuel delivery system. (especially if you are looking for a leak!) Also, do not use your hands to feel for leaks while the engine is being turned over or running. diesel fuel systems operate at extremely high pressures.
 
Seth_O

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Ok, reviving an old thread: I took my M35 out today and it stalled out on me several times. It behaved as if starved for fuel. I found I could (barely) keep the engine running if I pulled out the hand throttle anytime I came to a light and kept the RPM's north of 1500. Over time the issue got worse until eventually I couldn't keep the engine running unless it was under significant load (accelerating.)

When I finally looked under the hood there was a significant amount of fuel on the IP, nothing higher than the area mentioned above (the round piece the injector lines are plugged into.) Is this common? Search turned up half a dozen or so threads that are similar (although only one or two exactly the same) and is it generally just a matter of replacing some seals?

Which manual should I reference for servicing the IP? There's so many on the site I struggle to find the correct one :(.

Cheers.....
 
Seth_O

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Ok, for anyone else using the search function (as I was when I ran into this) here was my issue: the 'box' housing fuel shutoff valve (engine stop valve) was leaking around the edges. I removed the box to find that the gasket underneath was some sort of metal fiber gasket, and the fiberous material was completely worn away and disintegrated. So all I had were the metal fibers! Additionally the valve linkage where the fuel enters the pump assembly (HH?) was leaking from several junctions. I pulled that all apart, cleaned it up, and reassembled using teflon tape. I fired the truck up and let it idle for a good 30mins, and no leaks.

I do find though that I still have a very small amount of fuel coming from a round vent or adjustment knob on the cap where the fuel lines run to the injectors. Still working this one out.

JD: since I was working on the fuel system anyway, I went ahead and changed out the 2 main fuel filters. I have never seen anything to disgusting. It's a wonder that the engine was even running, let alone running as strongly as it was pre-leak.
 

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Floridianson

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Seth_O said:
Ok, for anyone else using the search function (as I was when I ran into this) here was my issue: the 'box' housing fuel shutoff valve (engine stop valve) was leaking around the edges.
Click to expand...
Thought that if you found fuel in what you are calling the shut down box the you have to replace the O ring that is behind the shut down lever that is in the HH.
Was it leaking fuel or oil?
 
Seth_O

Seth_O

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Floridianson said:
Thought that if you found fuel in what you are calling the shut down box the you have to replace the O ring that is behind the shut down lever that is in the HH.
Was it leaking fuel or oil?
Click to expand...

Hmmmm, good question. For a brief period I was running a mix of WMO and diesel, what I found in the area where the fuel shut-off cable attaches appeard to be oil, so I assumed the WMO had somehow pooled there and remained.

It's totally possible it was just oil, and the fuel I was finding around the casing was blow-back from the fan moving the leaking fuel from the fuel line connections at the front of the HH. I wasn't aware the fuel shut-off mechanism was lubricated by engine oil, that makes quite a bit more sense.
 
deathrowdave

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2 Orings under HH . They are standard Orings you can get them from any large gasket company in your area. I had a few in stock at one time but have exhausted all my stock. Be careful looking for leaks while engine is running very high pressure .Have a great and safe day,Dave
 
Floridianson

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deathrowdave said:
2 Orings under HH . They are standard Orings you can get them from any large gasket company in your area. I had a few in stock at one time but have exhausted all my stock. Be careful looking for leaks while engine is running very high pressure .Have a great and safe day,Dave
Click to expand...
There are three O ring that you should replace two for the HH one for the fuel shaft.

You realy should not use standard but switch to viton O rings.

Grainger's has them part # AS568A-221 and AS568A-230 for the HH.
 
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Beyond Biodiesel

Beyond Biodiesel

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The IP on my M756A2 has been leaking since I bought it 1.5 years ago, and recently the dribble has turned into a spray. Now the driver side of my truck is getting coated with diesel fuel. So, I searched this forum for info on replacing the seals in the HH.

Floridianson said:
There are three O ring that you should replace two for the HH one for the fuel shaft.

You realy should not use standard but switch to viton O rings.

Grainger's has them part # AS568A-221 and AS568A-230 for the HH.
Click to expand...
I found Grainger no longer stocks the above item#
Tinwoodsman said:
I found this source the other day. They have over 250 sets in stock.

http://www.steelsoldiers.com/showthread.php?t=59343
Click to expand...
I found the link that is on the page that the link above points to no longer works.

I found this thread very useful for replacing the seals: http://www.steelsoldiers.com/showthread.php?14688-multifuel-fuel-pump-hydraulic-head-removel.

I would like to have the seals in hand before I take the HH apart. Does anyone have a more recent part#, or description of the seals needed so that I can order them from an o-ring house?
 
jbayer

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gimpyrobb

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Got any pics? The seals aren't the only thing that will let fuel spray out of the head. There is a 12pt plug on the side of the hyd. head that can crack and spray fuel.
 
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