Lesco Skid Sprayer pump help

Discussion in 'Pesticide & Herbicide Application' started by pomticks, Aug 28, 2010.

  1. pomticks

    pomticks LawnSite Member
    from Maine
    Posts: 37

    I am puzzled to a point I need to ask for help. I have a Lesco Skid 200 gal sprayer with a D403 Hypro pump. The other day while using it all of a sudden the pump oil resevoir looked like a black and tan. I replaced all the diaphragms in the spring. So usually when the diaphragms crack it turns the oil milky and it drains into the water, pressure goes bad, and oil is gone. Today I took off all 3 heads, inspected the diaphragms and no issues. Put is back together and ran it. After 20 minutes oil back to a milkshake. What else do I need to look at? Should I replace all 3 diaphragms even though they look good? Ideas, thoughts?? Thanks in advance.
     
  2. Pumptecguy

    Pumptecguy Inactive
    Posts: 71

    Quick thoughts:
    1) Your oil may have detergents or fillers that cause foaming.
    2) There is still some water inside the crankcase.
    3) There is a crack in the body of the pump that may be leaking into the crankcase.
    4) The diaphragms were installed incorrectly. (sorry)

    Such is the joy of diaphragm pumps....
     
  3. pomticks

    pomticks LawnSite Member
    from Maine
    Posts: 37

    Thanks for the help. I think I am going to replace all 3 diaphragms this morning but how do I get all of the water out of the case?
     
  4. Pumptecguy

    Pumptecguy Inactive
    Posts: 71

    The way it is usually done is with heat (after all the oil is drained out). Castings of this sort are often baked to remove the moisture. You will need to take the whole pump apart and dry the crankcase completely.

    Another 'trick' is to empty out all the oil and replace it with a water-excluding synthetic. There are some synthetics that will not exclude water (mix or emulsify) and some will. The milky oil is emulsified.

    The 'trick' is to run the pump hot (for a while) and let the water cook off. The sad news is if the water sits in there it will rust the insides of the drive system which you cannot afford to fix.
     
  5. RigglePLC

    RigglePLC LawnSite Fanatic
    Posts: 11,777

    I would replace the diaphragms. Often there is a tiny hidden crack near the center where the bolt goes through. If you can, tilt the pump for 10 minutes to remove the old oil. If not, I usually clean the old oil out with a paper towel. Cpmpressed air is a possibility--but messy--you would have to wash your whole truck, LOL!

    Don't install the diaphragms upside down, and be sure they are seated in the grooves for a good seal.
     
  6. pomticks

    pomticks LawnSite Member
    from Maine
    Posts: 37

    Thanks folks for the information. Come to find out one diaphragm had a slight pin hole in it that I didn't see the first time around. Ran it for a good hour, oil turned just a shade dark so I think I am going to run it for another hour and change the oil one more time. Troubleshooting gets fustrating...esp when its 90 degrees out and the sun is beating on you while working on the pump in the back of the truck...lol
     

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