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Dozer Fuel Incector Pump oil Leak

Forum Forums Bulldozer & Excavator Troubleshooting Dozer Fuel Incector Pump oil Leak

This topic contains 9 replies, has 3 voices, and was last updated by Bluenoser Bluenoser 1 year, 5 months ago.

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  • #46043
    Bluenoser
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    Further to a previous post. I had diesel coming out the lubricating oil dip port on my fuel injection pump (TY396 engine)    Took apart the diesel hand priming pump as suggested.

    There is an  O ring in the valve body that the piston priming shaft runs through. this appears to separate the diesel fuel side from the injector pump crankcase side.  I am replacing and hope this will solve the problem

  • #46044
    Bluenoser
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    Parts

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  • #46046
    Bluenoser
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    O ring

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  • #46048
    Bob Rooks
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    Yep, that’s it. Be sure to replace it with a nitrile one. There are quite a few manufacturers of those lift pumps, and they are all basically the same. The ones on my Mitsubishi and Yanmar diesels are identical, even according to the parts book illustrations. There aren’t any seals on the piston either. Hope that’s the issue, and not the other.

    Yuchai dozer, Mustang skid steer, Mitsubishi mini-ex, Dual Dozer w/twin laser receivers, '50 Ford COE transit mixer.

  • #46052
    Bluenoser
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    Hi Bob

    Hope you are enjoying retirement.

    Took me a while to figure out what was what and how it would worked , no parts diagram.  Everything inside looked good, a little wear on the fuel piston (polished a little bit on one side as opposed to the other) but not bad for 600+ hrs. Just finished bleeding the air (pain) and got her going. Filled the injector pump with oil and let her run up to temp. So far so good. Will monitor injector pump lub oil level and see how it goes ( at lease I know where to look next time). I believe you mentioned somewhere that you bought a new pump … who was the supplier?

    Cheers Brian

  • #46053

    Piper184
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    Hey thanks for posting the photos. I never would have guessed that there was only a lowly “O” ring between the lube oil and the fuel. Mine has been overflowing the lube oil for a couple of years but I figured it was the injector pump, not the lift pump. I just changed it often and lived with it.

    Because of your post, I took mine apart and even though the “O” ring made contact with the plunger shaft, it felt like it was none too tight. I found a replacement in my assortment. It was a little thicker cross section which made it a bugger to get pushed into the groove. There is now a much better seal between the lift pump body and the plunger shaft.

    Like you, only time will tell if this is the fix or not.

    Another option would be to install an electric lift pump and remove this one all together. It should be easy enough to manufacture a cover plate shaped like the gasket.

    Thanks again.

  • #46054
    Bob Rooks
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    FWIW, you can get these almost anywhere. Hook them up with a relay to your key switch. Takes care of the priming task too.

    http://www.jegs.com/i/Autobest/035/12D/10002/-1?CAWELAID=230006180002542447&CAGPSPN=pla&CAAGID=15769068431&CATCI=pla-191844202391&gclid=CjwKEAjwuuy4BRCvs43g9fX9mz4SJACiYydPB886QIoEyHgtoXUcGvNOW_TstukMmC7W5pnRWIOaARoCEKDw_wcB

    Yuchai dozer, Mustang skid steer, Mitsubishi mini-ex, Dual Dozer w/twin laser receivers, '50 Ford COE transit mixer.

  • #46055
    Bluenoser
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    I was amazed as well that the small O ring was the only thing separating the injector lub oil and fuel side .. but there it is.  Yes it is a tight squeeze to get the plunger back in.

    I like the electric pump idea.  :good:   Would eliminate the possibility of contaminating the injector lub oil with diesel and destroying the injector pump.    Supply side diesel fuel pressure @ 4 – 7 psi is low so regular diesel fuel lines should work.

  • #46056
    Bob Rooks
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    I have seen a couple of new compact excavators with no mechanical lift/priming pump at all, just an electric pump. This may be the future for OEM’s. I know if mine ever fails again I’ll just toss it and install an electric. My F-350 6.4 diesel has an electric fuel pump.

    I bought my pump from Tommy at Affordable. It should be noted that there are two configurations for the lift pump – priming plunger can be on the right or left side, and this has to do with how the check valves are installed. The arrangement might be able to be changed in the field.

    Yuchai dozer, Mustang skid steer, Mitsubishi mini-ex, Dual Dozer w/twin laser receivers, '50 Ford COE transit mixer.

  • #46057
    Bluenoser
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    OK Thanks Bob

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