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Question for Those With Oil Pumping Systems

Discussion in 'CNC IN THE HOME SHOP' started by MontanaAardvark, Apr 9, 2017.

  1. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    This may be one of those dumb newbie questions, but I know this is the place to ask.

    I built an oil distribution system for my G0704 conversion based on Hoss' DVD plans. (Somehow I ended up hijacking someone else's build log here. I was posting there comparing stuff and something derailed him from keeping working on it, so I just kept posting. )

    I got the system debugged and running, and the mill has been sitting for a couple of weeks without running. Wednesday, I went behind the mill for something and found a puddle of oil on the floor. My oiling system has been dripping oil. To shorten this somewhat, I did everything I could think of to find where it's coming from, and eliminate sources, but I still get a couple of drops of oil every hour. It seems to be coming from the pump itself.
    Bottle_Pump.JPG

    This is one of those "universal" car fuel pumps. Why? Because it's what Hoss used. Got it from an eBay auto parts seller. Low pressure (4-7 PSI), but it will pull the oil out of the bottle when the tubes are empty and pump it up onto the mill base. What I find is that when I dry everything off, the oil fittings (which are 1/8-27 NPT tapped, composite, push in fittings) are dry, but I get some oil on the frame of the pump at that bottom corner. You can see a drip on the bottom corner of the pump frame here. There's some black foam that I mounted under the pump (to reduce noise) on the right that's also getting wet with oil and ready to drip, too.

    Leaking.JPG

    Again, the areas around the fittings are dry. The fitting on the bottom left would have a drop on it if it was leaking, and the one on the top is dry to the touch. It would probably be letting a drop run down the plastic tube to the right, but the tube's dry.

    OK - newbie question time: is this normal? Does everyone's pump leak from the body of the pump? Should I get a different pump or what? Ideas?


    Bob
     
  2. JimDawson

    JimDawson Global Moderator Staff Member Director

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    I would think a leaky fuel pump would be a real problem in its intended application. Not so dangerous in your application, but if it was dripping gas........yeah that could be a problem:blowup:
     
  3. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Yeah, me too. My wife is hammering that oil is not gasoline, and the viscosity is different. It is, but in the way that oil ought to be better, I think. It's 0-20, so a very light oil, but more viscous than gasoline.
     
  4. Ulma Doctor

    Ulma Doctor Infinitely Curious Active Member

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    Hi MontanaAardvark,
    there appears to be a fitting to pump body leak
    if you can, remove the fitting from the pump body and re-seal the fitting threads with teflon pipe tape and reassemble.
    if there is an o-ring present on the mating surfaces, inspect those or replace
     
  5. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    At this point, pulling the fittings adding some Teflon tape or pipe dope would be the easiest thing I can do and worth a try.

    Is it necessary to flush all the oil and clean out the fuel pump with mineral spirits or something? I don't know I could ever get it clean as new.


    Bob
     
  6. terrywerm

    terrywerm New Member Liaison Staff Member H-M Supporter-Premium

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    I would think that if you can tip the pump up so that you can get all of the oil removed from the threads, you should be just fine.

    When working on fork lifts or heavy equipment, I use a thread sealer from Caterpillar that works even if oil is present. It is meant for transmissions and hydraulic systems. Do I expect you to run right out an buy some?? No. I am only mentioning it so that readers are aware that it is available. Eaton also makes a similar sealer for the same usage. No matter who you get it from, it is expensive but it works great.
     
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  7. FOMOGO

    FOMOGO United States Active User H-M Supporter-Premium

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    The Teflon tape or paste shouldn't really be affected by a little oil, if that is really the issue. Leaks often aren't coming from where they appear to be coming from, but fittings and seals are always a good place to start. Before diving in wipe it down with some solvent and demount it from the machine and pull your foam pad so every surface can be inspected, after an hour or so, use a small piece of paper towel to find the actual source of the leak, be sure to check any lines up stream of the pump. Good hunting, Mike
     
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  8. benster

    benster United States Iron Registered Member

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    You're probably just not getting even oil flow to all ports at once. So when one port is just getting oil another has, and is just leaking the extra oil. It will seep under the base and out the stand. This is what I'm trying to fix but don't want to spend a lot on flow valves, so I might make some.

    Sent from my Nexus 5X using Tapatalk
     
  9. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    I think the pump must be bad. I just took it all apart, drained it and cleaned the threads, then put it together with teflon pipe dope on the threads. Now it won't pump oil at all, it just sputters drops into the outlet tube.

    I ran it until the pump is too hot to leave my hand on (130?) and it never turned into a full flow in the tubing. Plus, it's leaking from the fittings.

    The last time I ran the pump (two weeks ago?), it was fine. A solid flow of oil (visible in the tube) was at the mill's base in under a minute. It never took more than five minutes at worst to pump from a dry system to the fittings, now I've left it on for 15 minutes after several more minutes of trying with another power source. The input tube is full, the output tube is a mix of air and oil.
     
  10. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Well, I took it apart and rebuilt it yet again, this time with different press-in fittings, and have it almost fixed. Almost.

    Overnight, 16 hours, I got one drop leak. If I do feel oil, like a couple of hours ago when I checked for leak after the 16 hour overnight wait, it's still along the bottom edge of the pump frame. That would imply the pump is probably OK and it's either that I can get another tiny tightening of the output connector, or it's coming from somewhere else.
     
  11. TomS

    TomS Active User H-M Supporter-Premium

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    I gave up on the push-to-connect fittings because of leaks. I now use NPT to 1/4" compression fittings and don't have that problem anymore.

    Tom S.
     
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  12. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    This.

    This is sounding more and more like The Wisdom of the Ages. I was thinking of barb fittings, maybe with a clamp over them. I need a big step down, from 1/8-27 NPT to 5/32 tubing, though.

    Right now, I'm in the category of leak that lots of people put up with out of cars or motorcycles or whatever. 2or 3 drops per day. The floor is epoxy painted concrete, so it will stay there and is a slipping issue, except that I will hardly ever go behind the mill. If I had left it bare concrete, it would soak into the concrete like my old concrete driveway. Maybe a plastic tray with some absorbent in it.
     
  13. TomS

    TomS Active User H-M Supporter-Premium

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    Can't say that I've seen a 1/8" NPT to 5/32" compression fitting.

    Tom S.
     
  14. MontanaAardvark

    MontanaAardvark United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Tom's answer was the answer. I also couldn't find compression fittings, but I could find barb fittings. It took a little adapter, but looks like this.

    NewPlumbing.JPG
    Since I'm using 5/32 tubing (1/8 ID), I had to adapt from the fittings I could find to that with a short piece of 1/4" tube.

    So far we're at 2-1/2 days without one drop leaked.


    Bob
     
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