Hydraulic Head Question

[GunInstructordotcom]

No plunger ? They need to fit the plunger to the Hydraulic Head. So they must sell the plunger with the head.

The HH does not come with the button and retainer. Is that what was meant here? The plunger is the core of the HH, so it would have to be included, along with the metering block that is held in by it. There is a good thread here about someone who tried to rebuild an HH and the difficulties involved. It certainly convinced me not to try.

 

[rustystud]

The HH does not come with the button and retainer. Is that what was meant here? The plunger is the core of the HH, so it would have to be included, along with the metering block that is held in by it. There is a good thread here about someone who tried to rebuild an HH and the difficulties involved. It certainly convinced me not to try.

I'm pretty sure the poster just got some "misinformation" along the way.
I posted that rebuild thread. I didn't just try but did rebuild several injection pumps. In fact I rebuilt four of them. Of course I've rebuilt injections pumps before at work so it's not like I just decided one day "hey lets rebuild this injection pump" kind of thing.

 

[NY Tom]

The HH does not come with the button and retainer. Is that what was meant here? The plunger is the core of the HH, so it would have to be included, along with the metering block that is held in by it. There is a good thread here about someone who tried to rebuild an HH and the difficulties involved. It certainly convinced me not to try.

Yes this is what I meant. An error on my part thank you.

 

[GunInstructordotcom]

I'm pretty sure the poster just got some "misinformation" along the way.
I posted that rebuild thread. I didn't just try but did rebuild several injection pumps. In fact I rebuilt four of them. Of course I've rebuilt injections pumps before at work so it's not like I just decided one day "hey lets rebuild this injection pump" kind of thing.

It wasn't your threads. It was someone who had never worked on hydraulic heads. In the thread, his first attempt was unsuccessful and if I remember right, it was because the worn out plunger was leaking. I'm guessing that thread is over 10-12 years old. I thought I had bookmarked it but I didn't. He ended up successfully rebuilding his HH.

 

[Elk1111]

I have done it but I can’t remember if I wrote much about it. The only part that is difficult and I recommend soaking it a few days in ATF or kroil is getting the star shaped bolt out from the side of the head. It can crack if your not careful.
I had to rebuild mine because it was a g pump with no replacement heads available anywhere.

 

[rustystud]

I have done it but I can’t remember if I wrote much about it. The only part that is difficult and I recommend soaking it a few days in ATF or kroil is getting the star shaped bolt out from the side of the head. It can crack if your not careful.
I had to rebuild mine because it was a g pump with no replacement heads available anywhere.

Yes those "G" pumps are getting as rare as "Hens-teeth" . I had one but it was just a pile of junk. Should have kept it anyway just as a visual aide.

 

[rustystud]

It wasn't your threads. It was someone who had never worked on hydraulic heads. In the thread, his first attempt was unsuccessful and if I remember right, it was because the worn out plunger was leaking. I'm guessing that thread is over 10-12 years old. I thought I had bookmarked it but I didn't. He ended up successfully rebuilding his HH.

I don't remember that post. Of course I don't remember what I ate for breakfast either !

 

[GunInstructordotcom]

I obtained another new HH which just arrived. I got everything back together today and started it up. It ran fairly nice for a bit and then would not idle again. Perhaps air in the system. I set the throttle and took a look. Then I noticed a decent size leak around the HH area. I shut it down and was so frustrated I just put things away and tomorrow I'll start it again and try to determine what is leaking. It might be the brass fittings I transferred over from the old HH. I used a small amount of TFE paste on the male threads of both brass fittings. It could also be old hydraulic line fittings at the HH. I had to replace the #2 line because it had been cross-threaded at the injector and was ruined. Yes, I did that, but I believe it was already cross-threaded before I removed it. Maybe in an army shop years ago or maybe the last time I tried this two years ago. The female threads of the injector are not damaged, so the line male threads must be softer steel.

By the way, what worked really well for me when lining up the red tooth and installing the shut off shaft in the side of the HH was a small rectangle mirror with a telescoping handle that I could position so I could see the side opening of the injector. It also helped when installing the linkage and Jesus clip. The view is upside down so you have to move pliers, linkage or whatever in the opposite direction that your brain is telling you to do. I got used to that after a few minutes of frustration. I put a few rags below the linkage in case I dropped the clip and sure enough it went on the linkage the first try. I did drop one of the two screws for the side cover and the rags caught it, so it is a good idea to position a rag "trap". Experienced mechanics probably know all this but I'm posting it for the miserable wretches like me who are new to multifuel mechanics. I will let everyone know what happens tomorrow.

And bonus! My engine oil is contaminated with diesel so I have to change oil I just changed two years ago and never used. Sigh.

 

[rustystud]

Well look on the bright side. The engine runs now ! The other stuff like leaking oil and fuel and such, is just a minor inconvenience. Remember, don't sweat the small stuff.

 

[Elk1111]

Did you replace the orings when you installed the head?

 

[GunInstructordotcom]

Did you replace the orings when you installed the head?

I didn't have new ones when I installed the latest HH. I had the new ones I installed with the old HH that just sat in the engine without use for about two years. They looked quite new soft and "plump" but maybe that was a mistake. I just received a new set so maybe better safe than sorry, bite the bullet and go back in and replace them? But first let me get on this and see if I can determine the source of the leaks around the HH.

 

[GunInstructordotcom]

The leaks at the HH are: The brass "T" fitting on the side of the HH where it threads into the HH. My mistake, I could have gone one more revolution so I will. The other leaks are several of the injector lines where they thread into the new HH. I have two new lines, #1 and #3. They are not leaking. I believe it is #2 and #4 leaking. I have some questions that mechanics experienced with this will probably know the answers to. Do old injector lines wear out the compression ferrules after many on and offs? Is it possible that the new HH has slightly different depths that the ferrules sit in? I tightened the lines going into the HH decently tight with the correct flare nut wrench that is about nine inches long. Do I go hella tighter to see if the leaks stop or can I strip the threads doing that? Thank you for your time and effort for answering in advance.

 

[Floridianson]

As far as the injector lines tips wearing out no. They're actually supposed to spin so whenever I'm doing an injector line I check to see if it spins. If I can't get it to free up or spin the best thing to do is put a little touch of grease on the part of the tip that meets the injector or the head and the jam nut to the tip. Also we were inspecting the line tips we look for any chipping.

 

[GunInstructordotcom]

As far as the injector lines tips wearing out no. They're actually supposed to spin so whenever I'm doing an injector line I check to see if it spins. If I can't get it to free up or spin the best thing to do is put a little touch of grease on the part of the tip that meets the injector or the head and the jam nut to the tip. Also we were inspecting the line tips we look for any chipping.

The tips looked pretty rough on a few, so I replaced them with new lines from Memphis. Same lack of idle when I start it up. I read many threads on this issue and got some ideas on what to check. I took off the side cover to check the free motion of the linkage and noticed a bit of diesel in the cover. I replaced the o-ring on the metering shaft and noticed that Big Mike's new o-ring is smaller than the one I had on there. Big Mike claims his is the correct size and allows the bracket to be tightened completely per Ambac instructions. Sure enough I was able to tighten both screws completely and the linkage moves freely. Next I checked the drainage of each fuel filter. The secondaries were clear diesel. the primary was diesel and about ten tiny pieces of rust, from the tank I assume. All filters were replaced last time I worked on this and I have not run the truck since then about 2 years ago. I'll start it up tomorrow and see what happens, but I suppose it would not hurt to pull my fuel pump and check it to see if the intake is clogged if it still will not idle tomorrow. Also I will check for leaks again where air might be getting in. Does all this sound right to more experienced multifuel mechanics?

 

[GunInstructordotcom]

The tips looked pretty rough on a few, so I replaced them with new lines from Memphis. Same lack of idle when I start it up. I read many threads on this issue and got some ideas on what to check. I took off the side cover to check the free motion of the linkage and noticed a bit of diesel in the cover. I replaced the o-ring on the metering shaft and noticed that Big Mike's new o-ring is smaller than the one I had on there. Big Mike claims his is the correct size and allows the bracket to be tightened completely per Ambac instructions. Sure enough I was able to tighten both screws completely and the linkage moves freely. Next I checked the drainage of each fuel filter. The secondaries were clear diesel. the primary was diesel and about ten tiny pieces of rust, from the tank I assume. All filters were replaced last time I worked on this and I have not run the truck since then about 2 years ago. I'll start it up tomorrow and see what happens, but I suppose it would not hurt to pull my fuel pump and check it to see if the intake is clogged if it still will not idle tomorrow. Also I will check for leaks again where air might be getting in. Does all this sound right to more experienced multifuel mechanics?

I started it up and it idled great. All looked good except I'm not sure if the side cover is weeping diesel or not. It could be residue from before. Before I button everything back up, injector line clamps, bolt down the heater box and so forth, I will pull that side cover just to be sure it is not still leaking diesel.

 

[GunInstructordotcom]

I started it up and it idled great. All looked good except I'm not sure if the side cover is weeping diesel or not. It could be residue from before. Before I button everything back up, injector line clamps, bolt down the heater box and so forth, I will pull that side cover just to be sure it is not still leaking diesel.

Good news. Just a bit of motor oil in the side cover as it should be. Anyone who has issues with idling after replacing the HH o-rings should try Big Mike's metering shaft o-ring. In my opinion (and Big Mike's), the whole loosening of the clamp to achieve idle issue is due to oversized o-rings. Now it is time to change all the differential, transmission and transfer case oils. From what I have read here, the correct oil for the transmission is non-detergent 30 weight motor oil? And the diffs are 80-90 gear oil? What about the transfer case?

 

[Jeepsinker]

Fyi, you probably won't strip the threads in the hydraulic head by tightening the piss out of the injector lines, but you'll cause the head to develop hairline cracks that leak fuel.

I can't prove it, but my opinion is the injector line ferrules do get compressed and fail to seal, maybe not from being taken on and off a lot, but probably from being overtightened.