Why do the Hydraulic Head clips fall off.

TsgtB

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I know people say the deuce will run without an "in tank" pump.
I am just wondering if that could be a contributing factor for the HH to fail?

A lof of the "no start" post seem (to me), to include a faulty pump as well as the HH failure.
 

tommys2patrick

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Kind of amazing and somewhat comforting to know that at least it kept running even if under less power. I suppose for a military vehicle this would be a good thing in combat. I wonder if it was designed that way for that reason?
 

red

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Don't know if it was designed that way. During the return trip I didn't risk turning the truck off because it was being difficult to start on the way down (pumps were going out and I hadn't realized it yet). Good thing, because after that trip the truck would not start until the pumps were replaced.
 

Floridianson

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Study exactly what happens when one pulls on the engine shutoff handle of the cable to the thingamahjig which moves the whatisit.
You might not want to just yank on the cable to stop it.
One is operating a valve within a complicated mechanism.

maybe see post 32 in here
http://www.steelsoldiers.com/showthread.php?78640-stuck-in-full-throttle-multi
Just to be correct the thread above post 32 line #2. When the control collar is up it holds the spill port closed longer and we get high RPM. When the control collar is down the spill port is open longer and all the fuel spills out and we get a no fuel or shut down.
 
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frank8003

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This is about hydraulic heads, buttons, retainer clips, and a sophisticated mechanism.
So it is raining cats and dogs and lightning and nasty things out here, can't even get to the grill, and I am studying, Labor day noon. Oh, and the clothes dryer just failed.
I have always wanted to know how the fuel cutoff works without me having to take the truck apart to fix it after it broke. I want to know what can fail the mechanism. I have read all the posts I can find about the button, HH and the "lever" mechanism.
My anxiety is that one day I won't be able to shut it off normally, it would run away or I would have to crimp the fuel line to get it to stop which would damage the plunger/sleeve and I will have a dead truck.
So far I think this.
Start the engine once in a while, warm it up properly, idle it for five recommended minutes and slowly pull on the engine shutdown cable. All this also leads me to ask ...........

"When is the most pressure and when is the least pressure on the button and is the button ever supposed to see clearance between its surface and the flat tappet guide surface"?

I have attached four page PDF for your perusal to help answer my question.
View attachment fuel shutoff and the button 09072015.pdf
 

Floridianson

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No the plunger never leaves contact with the tappet. The only way to check that a fuel control is sticking is to remove the shut down cover and check for free movement of the control.
If it means anything to you when the cam lobe is up and the plunger is on it's injection stroke would be the most pressure on the plunger/button.
If you really worry about a run away just start the truck in high range 5th gear and if the rpm does not go to idle but starts to climb just kill the engine with the clutch and the brakes.
 
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gimpyrobb

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I have said it before,

This is only my opinion!

I think the piston sticks in its bore and when the lobe goes down, the button falls off.

The problem is then compounded by the lobe coming up and (now that the button isn't where its supposed to be) it pushes the piston farther up, which is why some get stuck in the "up" position.

That also pushes the piston into a potentially "non-lapped" section of the head which damages the finish on the piston/cyl walls.
 

rustystud

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I have said it before,

This is only my opinion!

I think the piston sticks in its bore and when the lobe goes down, the button falls off.

The problem is then compounded by the lobe coming up and (now that the button isn't where its supposed to be) it pushes the piston farther up, which is why some get stuck in the "up" position.

That also pushes the piston into a potentially "non-lapped" section of the head which damages the finish on the piston/cyl walls.

That makes a lot of sense Chris. I know diesel engine oil can get more "gummy" when sitting for long periods of time then regular gas engines can. Due to the diesel fuel that gets into the oil naturally from normal operation.
 

Floridianson

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Something has caused the plunger to stick the first time before the button fell off. I posted a pic of the plunger and a dark coating from ether bad fuel or water and the fuel control collar was sticking pretty good on it. What ever the cause it seems to happen more and more often. I have trucks that sit for months and have not had any problems yet. Yes I guess you could compound the problem Chris but the first problem of the button coming off all ready shut us down so the Head is coming off.

Frank8003 look for a thread where someone found a nice intake air shut down to control a stuck fuel control problem.
 
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Keith_J

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Cleaning the plunger and bore with B12 Chemtool, then lapping the piston with clean diesel and holding the plunger in an electric drill has worked for me. I noted milky yellow diesel after 30 seconds of lapping.

Never use any abrasive.
 

DavidWymore

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Cleaning the plunger and bore with B12 Chemtool, then lapping the piston with clean diesel and holding the plunger in an electric drill has worked for me. I noted milky yellow diesel after 30 seconds of lapping.

Never use any abrasive.

Never never never never never never :)
 
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