Hydraulic Head Leak

[dutchguy]

Seems like a new leak has developed. The PO of my Deuce (a SS member, so I'll reserve my opinion) tried a little "sealer" on the hydraulic head, I'm not sure why. I replaced #3 fuel line, as its fitting was leaking. All was dry until just recently. Now, it appears that I'm getting quite a bit (a drip every 2 or 3 seconds) of a leak from the screw shown in the attached photo, with the arrow pointing to it. If I can get the gunk out of the socket in this screw, I'll try to remove it, or tighten it. I've checked out the FI pump tech manual, but can't find a description of what this screw might have under it, or what it does. Any tips?

 

[phil2968]

Wow, that's all I can say. That is not how to repair a leak. What is that stuff? Who did you say put it on there? Gimpyrobb? Just kidding!

 

[doghead]

They are known to crack/split, starting at those set screws(actually a bleeder port).

 

[phil2968]

It looks likes a rebuilt head. No green paint and the Ambac plate. Looks just like the one I put on my bobber.
A crack in the head means a replacement. Floridainson had some in the classifieds.
http://www.steelsoldiers.com/parts-sale/88985-rebuilt-amboc-hh.html

 

[pctrans]

That is the exact spot where Canadian Gunner's head started leaking on his trip up to Canada. The head has a crack that starts at that point and does nothing but get worse. Replace the head!

 

[kennys@wi.rr.com]

I have to agree with what everyone else has said, they tend to crack right at those set screws. If you are lucky the sealant just gave out and it's now leaking past it right at the same point as the set screw. What probably could have been fixed with a new set of o rings is now a big sealant mess. Sorry that you are in this mess now. I am sure I still have some o rings left if you need them.

 

[dutchguy]

Ahh, boy. Well, one of the procedures that I've read up on the most is the hydraulic head replacement, with the plunger button, clip etc. This will be a great opportunity to bond some more with my "girl". Thanks y'all for the help.

 

[dutchguy]

I have to agree with what everyone else has said, they tend to crack right at those set screws. If you are lucky the sealant just gave out and it's now leaking past it right at the same point as the set screw. What probably could have been fixed with a new set of o rings is now a big sealant mess. Sorry that you are in this mess now. I am sure I still have some o rings left if you need them.

My understanding is that there are three O-rings. If that's correct, would they be the upper and lower that seal the HH to the IP housing, and the third being on the fuel shutoff rod where it enters into the housing under the HH?

Thanks.

 

[kennys@wi.rr.com]

That is correct.

 

[dutchguy]

Update on my leaky Hydraulic Head. After swapping the head yesterday, I did a close inspection of the head that I removed. I see no cracks, or other potential causes of the leaky #3 port. Of course, I suppose the crack could be small enough to be invisible. After reviewing a few old posts regarding clogged injector nozzles, I've started to wonder if that has been the issue all along. I guess that's why experienced mechanics are worth their money! The rest of us read the forum posts, and take a stab at it!
My original problem was fuel leaking from around the tube nut on line #3. Tightened, loosened, re-tightened, installed a new line. The new line helped for a while. Then fuel started leaking from the allen screw that holds the seal plugs in the horizontal passage, again, line #3. Now I have the new HH installed, and I've decided to replace #3 injector nozzle before I fire it up. If it's blocked, it would most likely blow something in the HH, which might have been the reason that the original owner (or the military, not sure) replaced the HH in the first place.Then I'll get the nozzle rebuilt and have a spare.
The truck has run OK since I've had it, especially after I cleaned the fuel system completely, changed filters, and run straight diesel. I've always thought that it had a slight miss, but have not been sure. We'll see if this helps.

 

[dutchguy]

Update: Got my new injector nozzle and fuel lines, but first things first. Decided to pull the valve cover, and make sure we were all lined up on the compression stroke. All good there. Replaced the #3 injector, got all the lines installed. After torquing the injector end, cracked them back open, and cranked her until we had good squirts. Tightened it all back up, cranked again and she fired right up. Sounded so smooth. Took a test drive, and she's running really well. I'm thinking we were a tooth or two out on the HH (cutout in the quill right, but red tooth on the HH not right), and the #3 injector partially plugged. Learned a lot, and didn't seriously wreck anything. It's all good.

 

[Flyingvan911]

Glad the repair went well.

 

[RAYZER]

my hh is leaking from the fuel control valve bolt on the side of the head.I removed this bolt and noticed that there is a very thin flange surface in the hole which the tapered end of the bolt seals against,metal to metal.there are passage holes on eather side of the thin flange ,i think the flange is cracked between the two holes,allowing fuel to leak to the outside .

 

[dutchguy]

Ok, so I've taken the old girl for a couple of trips, got her thoroughly warmed up, and some highway speeds. Can't believe how good she's running. I have noticed one small thing. When cruising along part throttle at say 35 mph, when I push the clutch in and release the throttle, she'll almost die as the rpm's drop below 500 momentarily, then recover to the 800 rpm idle. She did die once, but started right away while still coasting. I'm suspicious that the fuel control rod could be sticking. When I installed the new O-ring, and tightened the two screws to snug level, the shaft was real sticky. I backed the screws out until the arm moved (just a fraction of a turn) and safety-wired them. I'm guessing the O-ring squeezes down on the shaft, making it stick.The shaft had a small amount of end play, so that's not a problem. Truck has great throttle response, smooth idle, and stable part throttle speeds. Is this a symptom of control rod sticking?

 

[gimpyrobb]

I would think its more a governor issue. Drive it for a bit and see if it clears up. I would put some "sea foam" in the fuel to help clean it up too.

 

[dutchguy]

I would think its more a governor issue. Drive it for a bit and see if it clears up. I would put some "sea foam" in the fuel to help clean it up too.

That's what I'll do. Thanks, I really appreciate your reply.