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Removing, rebuilding, reinstalling Hydraulic Head

roalcoal

Member
150
1
18
Location
poplarville ms
Yesterday the parts came in for the hydraulic head and it was cloudy so I took advantage of the situation. I put the hydraulic head back together and reinstalled everything. I just got the truck two weeks ago and bought it not running so who knows whats wrong with it I took a chance on the truck. I pulled the M931A2 around to jump it off and holy cow just a couple cranks on the starter and she fired rite up and ran like a top. Who knows how long its been since the last time it ran but its running now thats all that matters. Parts for these Hydraulic Heads are available at AMBAC International if anyone is looking.
 

tstone

Member
Steel Soldiers Supporter
144
17
18
Location
Westminster/MD
Finally getting around to replacing the seals in my HH. I've suspected a fuel leak through the worn o-rings as my crank case oil level would slowly increase and my oil pressure would drop after the engine warmed up. The most difficult part in removing the HH is that the injector lines at the HH were rusted between the nuts and the OD of the line. A good soaking with PB Blaster and a few days to set helped to keep the lines from twisting when removing the nuts.

I found the best way to rotate the engine was to gently pull the fan blade while the trans was in neutral. I've done this on other gas vehicles but didn't know if it would work on a diesel with the fuel injectors attached. It rotated fine as the pressure from the other cylinders must have been relieved through the injectors. The only down part is that the crank to cam ratio is 2:1 so it took a while to get the red mark lined up.

I could buy the o-rings in town tomorrow but I'd rather buy them from a member, anyone have a set?

Thanks to all who have posted on this thread, very helpful information.
 

Big Z

Member
137
2
18
Location
Nebraska
Couldn't figure out how to delete the post. I found the answer to my question in this thread. Pertained to the part with the dimple, that goes in the slot just above the spring on the HH. I picked pointing it up. It works, same as before. Unfortunately my truck still won't hold idle and dies under 800 rpm. I had my fun diving into it though. I think I'll pick up another set of fuel filters and plumb in a pressure gauge today.
 

Another Ahab

Well-known member
17,989
4,532
113
Location
Alexandria, VA
Couldn't figure out how to delete the post. I found the answer to my question in this thread. Pertained to the part with the dimple, that goes in the slot just above the spring on the HH. I picked pointing it up. It works, same as before. Unfortunately my truck still won't hold idle and dies under 800 rpm. I had my fun diving into it though. I think I'll pick up another set of fuel filters and plumb in a pressure gauge today.
Shoot, I was looking forward to a game....


To your credit, Big Z, you don't give up easily.

Hope you get this all figured out without a whole lot more trouble. I got this feeling that you will. :beer:
 

TsgtB

New member
478
3
0
Location
Granbury, Tx
I understand the engine needs to rotate to get the HH out of the IP.
My question is, if i have a motor (seized from a bad head gasket) that has an IP on it,
I should be able to get the HH off it IF i remove the IP from the block (?)
(to get the bowtie clip or other hard parts I could use).


OK, i guess that was just a dumb question...
(hope it comes off ok)
 
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gimpyrobb

dumpsterlandingfromorbit!
27,786
751
113
Location
Cincy Ohio
Either pull the IP from the block for later(there is more useful parts than just the hyd head) or you can pull the gear off the front if you just want the hyd head.
 

TsgtB

New member
478
3
0
Location
Granbury, Tx
Well, I got the HH off my "donor motor", it came out pretty easy, it was all in one piece.
(does the little button on the bottom always feel like its about to POP off...??)
I also took the IP off, came out pretty easy also, while i was at it I got the air pump, water pump and oil cooler off too.

If I'm (working alone) rotating the engine (via jackshaft) would it be a good idea to rotate it till i'm close to the harmonic balancer timing mark, before I try to be "close" the "v grove" in the HH gear.
Or should i just "blip" the starter and check a dozen times... ( still not as tuff as a solo engine swap)

Thank everyone so much for posting all this GOLDEN info, for the shade tree wanna be.
 

Radden

Member
42
7
8
Location
Lexington/Ky
I have what I believe is everything loose and have the red alignment mark like one on the pictures at the first of this thread which is just to the left of the casting pointer mark. Or should it be just below the casting mark pointer? I didn't want to exert to much force on trying to remove it Any help would be appreciated Thanks, Bob
 
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Davis Welding

New member
54
1
0
Location
Colorado
When I picked up my deuce a few weeks ago, it had a no start-no fuel issue. First, I found that the fuel shut off rod/actuator was gummed up and stuff in the off position. I fixed that, reinstalled and fired the truck. It went start to WOT and was just screaming!!! I hadn't hooked the shutoff cable up so it was a choir to get it shut down with whatever my panicked mind could find. I got that all fixed up, then I was driving it down the road and it just shut off much like described here. I was **** bent on it being the HH button. Well, I decided to dive into the fuel shut off and governor area as I knew there had been a problem with sticky parts there. Sure enough, the fulcrum lever and sliding sleeve (parts #7 and B on page 3-47 of TM 9-2910-226-34) were gummed up as well and had stuck in the no fuel position.

This is just another place and way for the IP to stop putting out fuel especially if the truck has sat for a long period of time or has been maintained in a less than desirable manner!
 

Davis Welding

New member
54
1
0
Location
Colorado
O-Ring Sizes:

Large O-Ring: 2.484 x .139 = -230 or 230 (depending on which standard)
Small O-ring: 2.109 x .139 = -227 or 227 (depending on which standard)
Actuator O-Ring: .426 x .070 = -013 or 013 (depending on which standard)


Just FYI for anyone looking at sizing these orings from a supplier that does not list by number sizes, the measurements here are ID measurements. The 013 is 9/16" OD (.566" actual) 227 is 2 3/8" OD (2.387" actual) and the 230 is 2 3/4" OD (2.762" actual) I'm not sure if this was mentioned already but I figured I would post it since I was caught out by this today!! No biggie, just had to run to the part store. Of course, I ended up replacing my orings for no reason as they were just fine but I wanted to make 100% sure as my MF is making oil from some place! I think it was the fuel shutoff oring as I found a lot of fuel behind the cover. Just making sure everything is A OK!!
 
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