Fuel Leak Injecter Pump Area - M35A2

[Beyond Biodiesel]

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.

That appears to be where my leak is, so I guess I will start with tightening it, because it might just be loose, since I had not tightened.

Thanks, jbayer, for the links and o-ring sizes.

 

[FloridaAKM]

Isn't the 12 point plug a precision fitted part? You may have to try several plugs to get one that seals & not leaks more. IIRC, wrenching on that is verboten.

 

[gimpyrobb]

Yes, thats a very specific part and hard to find the right one to fix it. I recommend NOT trying to tighten it, usually when they spray fuel, they are cracked. You might snap it if you torque it down. Youl5 need to find some to try on your hydr head, or find another hyd head. There is some parts behind that screw if you take it out, be cautious!

 

[Beyond Biodiesel]

http://www.steelsoldiers.com/showthread.php?134856-Hydraulic-head-o-rings-for-multifuel-injector-


http://www.steelsoldiers.com/showthread.php?72201-Hyd-Head-Replacement

The following numbers were in one of the HH threads, can't find it now.
Viton Heat Resistant O-rings Size 013
Viton Heat Resistant O-rings Size 227
Viton Heat Resistant O-rings Size 230

Post #8 of this thread:
http://www.steelsoldiers.com/showthread.php?129642-Diluted-motor-oil

Thanks, everyone for all of the input. This is a great site. Thanks, jbayer, for the list of o-rings needed. Is it one each. or more?

 

[jbayer]

It's (1) ea. for all three. The # 013 is for fuel control rod, other two under HH.

welldigger has them for like $12, or $14, for all three shipped.
http://www.steelsoldiers.com/showthread.php?134856-Hydraulic-head-o-rings-for-multifuel-injector post #1

 

[Beyond Biodiesel]

After reading through this, and other threads on this topic, I ordered a set of o-rings, removed the hydraulic head on my 1969 M756A2 ultrasonic cleaned it, then reassembled it. The engine still would not start.

I also found the plug on the side of the hydraulic head leaked badly, so I tightened it, but it still leaked badly, so I took the plug out, and cleaned the plug, and the hole, then retorqued it down. No leak, but still not start either.

I read through this thread again, and followed the reasonable recommendation to replace all of the fuel filters. I found none of the fuel filters had been replaced in decades. There was about 3" of sediment at the bottom of each filter sump. However, the engine still would not start. The engine does puff smoke when cranking it, but will not sustain combustion on its own.

My engine oil sump is pretty high from diesel leaking into it from the bad seal in the hydraulic head. So, the question for you all here is, is it possible that the oil level in the sump is too high and is preventing my multifuel engine from starting? Or, does anyone have another suggestion.

 

[Beyond Biodiesel]

I recently drained the oil from the engine sump, and put new oil in, and changed the oil filters. Still no start, so the no start does not seem to be related to the oil level.

I did notice when removing the hydraulic head that the head had to be 180° off from where it is supposed to be to get the hydraulic head off. When i reinstalled the hydraulic head, I then rotated the IP until the red marker was in the proper position, which might have been a bad idea.

So, I believe the no-start problem must be due to the IP being 180° out of sink, but I am not sure why it ran for 1.5 years before that, then just stopped running one day, and will not start now.

I plan to set the timing right, then try starting it again. If it still will not start, then I plan to remove the injectors and inspect, clean them, then reinstall them.

 

[gimpyrobb]

Usually when I've had the fuel system apart, the trucks require a quick snort of ether to get them to come to life. Once that has happened, they work normally from that point on. From what you've posted so far, I'd have the injectors serviced anyway. The trucks run SO much better with "dialed in" injectors.

 

[orren]

Your problem is the HH is not producing enough pressure at the low starting RPM's
to open injectors. Your may try to use the flame heater when starting; clean and test
before trying to use. If the HH has enough pressure at a little higher RPM's it should
start and run but not idle much below 1000 RPM.

I'm finding using fuels that are not very clean i.e. under 1 micro absolute or better
is wearing the HH's tolerances. I'm suspicious that the China and other rebuilt HH's
are using inferior parts that are too soft.


Please post your luck with this.

I recently drained the oil from the engine sump, and put new oil in, and changed the oil filters. Still no start, so the no start does not seem to be related to the oil level.

I did notice when removing the hydraulic head that the head had to be 180° off from where it is supposed to be to get the hydraulic head off. When i reinstalled the hydraulic head, I then rotated the IP until the red marker was in the proper position, which might have been a bad idea.

So, I believe the no-start problem must be due to the IP being 180° out of sink, but I am not sure why it ran for 1.5 years before that, then just stopped running one day, and will not start now.

I plan to set the timing right, then try starting it again. If it still will not start, then I plan to remove the injectors and inspect, clean them, then reinstall them.

 

[Beyond Biodiesel]

Thank-you for your suggestions. I just recalled that I see no movement of fuel though the transparent return lines when the fuel pump is on, or when cranking the engine. Perhaps this indicates a block in the return line, which might be preventing proper fuel flow?

 

[gimpyrobb]

Thank-you for your suggestions. I just recalled that I see no movement of fuel though the transparent return lines when the fuel pump is on, or when cranking the engine. Perhaps this indicates a block in the return line, which might be preventing proper fuel flow?

Or a bad in-tank pump. It might make noise but if the bottom of the housing fell off(often does) it will not pump fluid.

 

[orren]

Yes, this is a great place to start looking. I would pull the intank pump and clean filter
screen and as much of its insides as you can without totally tearing down the whole thing.
I've let mine soak in a strong soap overnight, too. Also, check for crap in tank. May
be worth while to clean tank out; it doesn't take much to block pump intake screen.
And check black hose on pump very carefully, too.

Good luck!

Or a bad in-tank pump. It might make noise but if the bottom of the housing fell off(often does) it will not pump fluid.

 

[Beyond Biodiesel]

Thanks, guys, this makes a lot of sense, because the deuce fuel tank is galvanized, and I have noticed that high melting point triglycerides had precipitated out of my WVO fuel blends coating the tank thickly with grease. So, I plan to pull the lift pump out of the tank, and inspect and clean it, plus flush out the fuel tank, and install a drain on the fuel tank.

I have been working on extracting the high melting point triglycerides out of my fuel blends, and have been successful at removing them. So, in the future all of my WVO fuel blends will be depleted of the high melting point triglycerides, so that they will not accumulate in the fuel tanks of my diesel vehicles. I will get back with you on this thread with my results.

 

[scboolitcaster]

I thought fuel was pumping out of the 12pt plug in the hh originally?

Sent from my LG-V410 using Tapatalk

 

[Beyond Biodiesel]

I thought fuel was pumping out of the 12pt plug in the hh originally?

Sent from my LG-V410 using Tapatalk

I also found the plug on the side of the hydraulic head leaked badly, so I tightened it, but it still leaked badly, so I took the plug out, and cleaned the plug, and the hole, then retorqued it down. No leak, but still no start either.

I am going to focus on cleaning out the fuel tank, and lift pump screen as recommended above, because it is clear to me my deuce was not serviced in 40 years. I have also been burning vegetable oil in it, and I can see fat accreted to the walls of the fuel tank. So, I will put a drain valve in the fuel tank, and scrub it all out with gasoline, and check to make sure the fuel and return lines are not plugged and get back with you all here.

 

[gimpyrobb]

I thought fuel was pumping out of the 12pt plug in the hh originally?

Sent from my LG-V410 using Tapatalk

If the fuel system is in-tact and the in-tank pump craps the bed, thr IP will still pull fuel and run the truck.

Once the fuel system is taken apart and air gets in there, you need the in-tank pump to bleed air from the fuel system.


Kind of a pandoras box.

 

[Beyond Biodiesel]

If the fuel system is in-tact and the in-tank pump craps the bed, thr IP will still pull fuel and run the truck.

Once the fuel system is taken apart and air gets in there, you need the in-tank pump to bleed air from the fuel system.


Kind of a pandoras box.

Originally the engine just would not start one day. I had noticed a leak from the 12pt plug on the side of the IP had gotten much worse, but I was in the middle of moving. The truck ran for about 2 weeks after the move, then would not start.

So, I worked on the leak, and fixed it, and it still would not start, so then I scanned this forum for help, and found this thread, and a few others on the same topic. I had noticed that the oil level had been slowly rising since I bought it 1.5 years earlier, so I followed the instructions here and ordered a set of o-rings, dismantled, cleaned and resealed the hydraulic head.

Once all together, and leak free, I purged the fuel system, confirmed ample fuel flow to the injectors, then tightened up the hard pipes, still no start. All I get is a small amount of black smoke coming from the exhaust pipe, but no sustained firing.

On this thread you recommended changing the fuel filters, which seemed reasonable. I had ordered a complete set of filters for my deuce, so I changed all of the fuel filters. Still no fire, but smoke.

Then I drained the oil, changed the two oil filters, and put fresh oil into the sump. Still no fire, but smoke.

Now, it seems reasonable that the fuel tank and screen for the lift pump, and/or the fuel and return lines are plugged, since it has become clear to me that the truck was never serviced since it left the military, and I have run it on waste vegetable oil since I bought it, and I can see crud in the fuel tank from vegetable oil, and I see no fuel flow along the return line, but I have verified ample fuel flow along the fuel line. So, I plan to work on that when I can get to it.

If scrubbing out the fuel tank does not work, then I plan to pull one injector for inspection. If it is excessively coked or excessively warn, then I plan to send them off for a rebuild, and/or buy a new set. Since I make my own diesel fuel having a spare set of injectors, and rebuilding them myself has become an annual service. So, I plan to learn how to rebuild them myself.

I also plan to put one injector on a hard pipe that is rotated out of the way, and crank the engine to see if the IP can make pop pressure, because the HH might just be too warn to do so.

 

[gimpyrobb]

Sounds like a good plan of attack to me. Have you tried a whiff of ether to get her to light off yet?

 

[Beyond Biodiesel]

Sounds like a good plan of attack to me. Have you tried a whiff of ether to get her to light off yet?

No. It used to fire up with the intake heater no problem, so I think I will focus on trouble shooting for now.

 

[rustystud]

Thanks, guys, this makes a lot of sense, because the deuce fuel tank is galvanized,

No Diesel fuel tank is ever "Galvanized" . Steel, stainless steel or aluminum only.