Seeking Advice on Replacing HH O-Rings in the Truck

[GunInstructordotcom]

Hello, everyone! I have owned my 1970 M35A2C since 1999. I have been blessed with not many repairs, just alternator and water pump. Now my fuel injector is leaking on top of the shut-off lever housing. Reading everything here and watching the various videos out there, there is much info about the actual work on the fuel injector, but little info on how to do it in the engine compartment. Looking at the clearances, it appears to me that removing the cab heater assembly would give me a more direct shot at the task. It appears that I can unbolt the shelf assembly from the frame, disconnect the air vent hoses, disconnect the heater fan motor wire, and then lift the assembly out and rest it on top of the engine without disconnecting the water hoses. I would rest it on a piece of plywood to avoid damage to anything. Does this sound competent to those of you more experienced at wrenching than I am?

Is there any tips you can give me before I tackle this job? I know about aligning the tooth once the side cover and the fuel shutoff shaft is removed. Do I bump the starter button to move the gear into alignment? If I do this before I disconnect the fuel lines, it seems there would be no messy consequences. Is it OK to align the gear after I remove the fuel shutoff shaft? I mean, that will not misalign the installation of that shaft with the tiny pin on the front of it?

I just finished replacing the radiator and replacing the o-rings in the CAV fuel injector cover on my Massey Ferguson tractor, so I do have a fair amount of recent wrenching experience. Thank you in advance for your advice.

Chris Ewens

 

[Elk1111]

Use a bar in the jack shaft with the truck in neutral with the wheels chocked. Bumping the starter will take you forever to get it lined up. I use a mirror to see inside the side of the window. Yes you do have to remove the cover and fuel shut off to see the red arrow.

 

[GunInstructordotcom]

Use a bar in the jack shaft with the truck in neutral with the wheels chocked. Bumping the starter will take you forever to get it lined up. I use a mirror to see inside the side of the window. Yes you do have to remove the cover and fuel shut off to see the red arrow.

Thank you for the prompt advice. Where is the "jack shaft"? I'm not familiar with that term.

 

[Elk1111]

It’s the short drive shaft between the transmission and transfer case.

 

[GunInstructordotcom]

It’s the short drive shaft between the transmission and transfer case.

Thanks. I'll give it a try.

 

[frank8003]

Thank you for the prompt advice. Where is the "jack shaft"? I'm not familiar with that term.

 

[MikeON]

Are you replacing the hydraulic head O rings, or just the fuel shutoff O ring?
I just last week replaced the hydraulic head O rings and fuel shutoff O ring. Did exactly what you said with the heater - left the water hoses attached and flipped heater onto top of the engine.
I put the transfer case in neutral, and the transmission in 5th gear, then turned the engine with a bar on the jack shaft. Kept crawling out from under the truck to check whether the red gear tooth was aligned yet. Would be much easier with a helper. It took a while. I used a mirror to avoid having to remove the fender. The hydraulic head would not come off with the red gear exactly aligned. I found that it had to be just ahead of the pointer.

 

[GunInstructordotcom]

Are you replacing the hydraulic head O rings, or just the fuel shutoff O ring?
I just last week replaced the hydraulic head O rings and fuel shutoff O ring. Did exactly what you said with the heater - left the water hoses attached and flipped heater onto top of the engine.
I put the transfer case in neutral, and the transmission in 5th gear, then turned the engine with a bar on the jack shaft. Kept crawling out from under the truck to check whether the red gear tooth was aligned yet. Would be much easier with a helper. It took a while. I used a mirror to avoid having to remove the fender. The hydraulic head would not come off with the red gear exactly aligned. I found that it had to be just ahead of the pointer.

Thank you for the advice. Replacing all three rings. My wife will be looking while I'm turning the jack shaft. That will make my life easier. Tomorrow is the big day. You may think this is a dumb question, but which way do I turn the jack shaft? Facing the front of the truck, clockwise or counter-clockwise, or does it matter?

 

[Elk1111]

She’ll be able to watch the red pointer and let you know which way to turn it. Just remember the head will slip right out when the pointer is where it needs to be. Don’t try to force it. As MikeON said it might be a little forward or back from where the pointer says it should be.

 

[GunInstructordotcom]

She’ll be able to watch the red pointer and let you know which way to turn it. Just remember the head will slip right out when the pointer is where it needs to be. Don’t try to force it. As MikeON said it might be a little forward or back from where the pointer says it should be.

OK, thanks. I have studied everyone else's mistakes described online, so I'm hoping I don't make the same mistakes. No one described what they did with the disconnected fuel lines on the top of the HH. I'm assuming I flag them for reinstalling, disconnect, loosen the line at the injectors, remove some of the clamps holding the lines together, and just gently move them out of the way.

 

[Elk1111]

I found it easier just to take them completely off. I just made a diagram for myself. I did a drawing of the top of the head and labeled each port with a number that matched each line starting with one at the front of the engine. I’d label each line also but once you do it you’ll quickly find out each line is very unique and will only fit in it’s own place.
It also a good idea to clean each line to make sure your getting good flow.

 

[frank8003]

I found it easier just to take them completely off. I just made a diagram for myself. I did a drawing of the top of the head and labeled each port with a number that matched each line starting with one at the front of the engine. I’d label each line also but once you do it you’ll quickly find out each line is very unique and will only fit in it’s own place.
It also a good idea to clean each line to make sure your getting good flow.

 

[Welder1]

Use a bar in the jack shaft with the truck in neutral with the wheels chocked. Bumping the starter will take you forever to get it lined up. I use a mirror to see inside the side of the window. Yes you do have to remove the cover and fuel shut off to see the red arrow.

for clarity you put the transfer case in neutral and the transmission in like 4th gear which is 1-1 ratio then use a bar to turn the engine with the jackshaft

 

[Elk1111]

Correct but 5th will be better. Even turning in 5th is not real easy. I use a large box end wrench shoved between the u joint and yolk.

 

[MikeON]

To determine rotation direction, I just looked at which way the fan would turn to blow air rearward, and turned jackshaft that same direction. Don't know that it matters which way you turn it.
Biggest problem for me was getting some of the injector lines loose at the HH. Two of them kept trying to twist with the nuts. I kept turning the nuts very slightly back and forth and using penetrating oil and they finally came loose.
I didn't remove the timing cover on the injector pump as some videos show.

 

[GunInstructordotcom]

Thank you, everyone, for these bits of information. I'm hoping it will make my try tomorrow much easier.

 

[frank8003]

Removing, rebuilding, reinstalling Hydraulic Head

I bleed the fuel filters after changing them, but nothing else needs it. That said, I came home to a pair of fully charged batteries & turned the power on the Deuce. Fuel is flowing back into the tank, so that pump is working fine as I thought. 10 minutes of the pump running & I decided to spin...

www.steelsoldiers.com

 

[GunInstructordotcom]

Here's where I'm at. Everything went smooth with removing the fuel cutoff cover and sliding out the cutoff shaft. The cotter pin that everyone loses flew off and my wife found it on the ground with a powerful magnet. The o-ring was flat. Now I'm removing each fuel line from the top of the HH. They are so stiff, I don't see how I can pull the HH up without removing the lines completely. So I loosened each line at the injectors. Injectors #1 and #6, the fittings don't want to turn without the line twisting with them. I read that I should use penetrating oil there and work them back and forth. Does that sound right? Also, do I remove the lines as a unit or remove all the clamps that hold the lines together? I just don't want to make mistakes here that others have overcome.

 

[frank8003]

Here's where I'm at. Everything went smooth with removing the fuel cutoff cover and sliding out the cutoff shaft. The cotter pin that everyone loses flew off and my wife found it on the ground with a powerful magnet. The o-ring was flat. Now I'm removing each fuel line from the top of the HH. They are so stiff, I don't see how I can pull the HH up without removing the lines completely. So I loosened each line at the injectors. Injectors #1 and #6, the fittings don't want to turn without the line twisting with them. I read that I should use penetrating oil there and work them back and forth. Does that sound right? Also, do I remove the lines as a unit or remove all the clamps that hold the lines together? I just don't want to make mistakes here that others have overcome.

Yes, for penetrating stuff to loosen it up. Use Kroil or the special SS mix (acetone/ ATF) that some swear by. You are correct in working any fastner back and forth to finally get it off, Not good to break stuff.
...............And give the Wife (soldier B) A BIG FAT ATTABOY and a kiss.
As working on this stuff, most would remove all six lines. They have only a very small hole thru them [bent special to fit precisely] and it would help if You assured they were clear as per design. One may use your best spray cleaner-outaugh stuff blown thru them. See post #12 fuel system PDF.
Fuel lines are just 1/4" OD with a .0625 hole thru from HH to injector, Who knows what kind of crap is in there , but that is a small job. Clean be good.
Work Work Work, will it never end.
Clean is good.

 

[GunInstructordotcom]

OK, here's where I'm at. I've been working on the deuce on days I am not working, so every few days I have some time. I installed the o-rings, oiling them a bit. Installed the HH. Red tooth is centered on the pointer as it was when I pulled the HH. Installed the fuel cutoff shaft with the new, oiled, o-ring. I watched a video where the mechanic said the way to verify the shaft is correctly installed is to turn it both ways and it should stop about where the screw holes for the u-bracket are. Mine did, though the left side went a bit further than the video showed. The plate bottomed out and I installed the u-bracket screws. I adjusted each screw so that it was backed-off a smidge from preventing the lever from turning. I safety-wired the screws. I installed the y-shaped cotter pin on the shutoff lever. Curiously, many stated that was difficult to do, but for me I just reached down with my fingers and snapped it in place. (Thank you, God.) I installed the cover and gasket. When shade arrives in a few hours, I will install the six injector lines. All lines have been sprayed-through with parts cleaner and all threads oiled and wiped dry with q-tips and rags.

I was wondering about something. I know, I probably installed the cutoff shaft correctly, but then I get those doubts. So my question is, when I start the engine, IF I did not install the shaft correctly, what will happen? And how would I immediately shut off the engine if the shutoff mechanism is not working?