Hd11 injection pump leak

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   I have a leak that looks like it’s coming from the center cap in the middle of the injection lines. Can I remove the cap? My fuel pressure gauge also reads just below the green and under a load it goes down to almost nothing. That’s the only leak I find, but that shouldn’t affect the pressure at the gauge should it? Changing the filters didn’t help the pressure. 

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7060 Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 16 Sep 2009 Location: Missouri Points: 1148	Post Options Post Reply Quote 7060 Report Post Thanks(0) Quote Reply Topic: Hd11 injection pump leak Posted: 13 Jun 2018 at 7:58pm
	I have a leak that looks like it’s coming from the center cap in the middle of the injection lines. Can I remove the cap? My fuel pressure gauge also reads just below the green and under a load it goes down to almost nothing. That’s the only leak I find, but that shouldn’t affect the pressure at the gauge should it? Changing the filters didn’t help the pressure.

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CAL(KS) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 18 Sep 2009 Location: Chapman, KS Points: 3786	Post Options Post Reply Quote CAL(KS) Report Post Thanks(0) Quote Reply Posted: 14 Jun 2018 at 7:25am
	i dont have any experience with that pump but you might have a partial blockage in bottom of tank or in shutoff valve at tank affecting pressure. is the pressure a new problem or always that way? alot of these systems have a restricter fitting somewhere and they can become plugged or removed by owners.
	Me -C,U,UC,WC,WD45,190XT,TL-12,145T,HD6G,HD16,HD20 Dad- WD, D17D, D19D, RT100A, 7020, 7080,7580, 2-8550's, 2-S77, HD15

7060 Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 16 Sep 2009 Location: Missouri Points: 1148	Post Options Post Reply Quote 7060 Report Post Thanks(0) Quote Reply Posted: 14 Jun 2018 at 8:49am
	I have a good flow when I pulled the filters off. I haven’t owned it that long, but it did run up in the green I thought and now at high idle it is right on the line between green and red which I think it says is 8psi.

CAL(KS) Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 18 Sep 2009 Location: Chapman, KS Points: 3786	Post Options Post Reply Quote CAL(KS) Report Post Thanks(0) Quote Reply Posted: 14 Jun 2018 at 8:52am
	transfer pump could be getting weak. check your owners manual and see what it says about it, probably the same thing my 16 manual says but i dont have it on me.
	Me -C,U,UC,WC,WD45,190XT,TL-12,145T,HD6G,HD16,HD20 Dad- WD, D17D, D19D, RT100A, 7020, 7080,7580, 2-8550's, 2-S77, HD15

Ian Beale Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 03 Oct 2011 Location: New South Wales Points: 973	Post Options Post Reply Quote Ian Beale Report Post Thanks(0) Quote Reply Posted: 14 Jun 2018 at 4:14pm
	There is more on those PSB pumps in here http://www.oldengine.org/members/diesel/Ambac/AmbacMenu1.htm We had a considerable round of the kitchen with the one on our AC 45 grader but that was a while ago. IIRC there is a copper washer under that plug, which is on the high pressure side so shouldn't be affecting your gauge pressure. The primary is a gear pump so it shouldn't be physically affected by changing filters. They can leak from the shaft seal but that ought to show up in the engine oil. The seal is a standard commercial one if you need one. Depending on which version you have the return restrictor is either a valve assembly screwed into the front port return line or an elbow with a restrictor hole same place. If you get to taking the injection head off there is a screw in fitting on the side of the head that has to come out before you can remove the head. It has a square section o-ring on the end which has to come out too - and apparently it is now made of "unobtanium". Edited by Ian Beale - 14 Jun 2018 at 4:19pm

Ray54 Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 22 Nov 2009 Location: Paso Robles, Ca Points: 4524	Post Options Post Reply Quote Ray54 Report Post Thanks(0) Quote Reply Posted: 15 Jun 2018 at 10:47pm
	Ian you sure the ring is square. The common leak in old Cat fuel pumps from the 50's is a O-ring. But after 60 years they all look square and when a new o-ring of corret size is installed leak goes away.

Ian Beale Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 03 Oct 2011 Location: New South Wales Points: 973	Post Options Post Reply Quote Ian Beale Report Post Thanks(0) Quote Reply Posted: 16 Jun 2018 at 1:33am
	Ray IIRC it gets a mention on here back quite a way when I was battling our AC 45 pump problems. As did the "unobtanium". I gather some of the later heads didn't have that oil (IIRC) feed but I've never seen one.

DMiller Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 14 Sep 2009 Location: Hermann, Mo Points: 31067	Post Options Post Reply Quote DMiller Report Post Thanks(0) Quote Reply Posted: 16 Jun 2018 at 6:24am
	I have a spare inj pump for my 7G, tried to have it looked at by a few rebuilders to make a good spare, seems parts for these PSB pumps are really Unobtanium.