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The JLG 40F Boom Lift Dilemma

Discussion in 'Other Construction/Demolition Equipment' started by od1, Sep 12, 2009.

  1. TJK

    TJK Member

    Joined:
    Jul 23, 2022
    Messages:
    9
    Location:
    Indiana
    Thanks again the manuals came through and are helping already. So I have it traced back to the back panel. The wire that heats up the ignition coil on + side and also goes to distributor is causing the voltage drop. Disconnected the distributor wire and voltage is same as battery. It has the electronic ignition in it and the module must be the problem. If I disconnect the coil wire from panel and jump it straight to battery I have 12.3 volts on the yellow wires when pedal engaged and everything works fine. I’m assuming my module is starting to short out in the distributor.
     
  2. OFF

    OFF Senior Member

    Joined:
    Sep 30, 2009
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    950
    Occupation:
    HD Mechanic
    Location:
    Alberta, Canada
    If you only have 10.2 volts with the ignition switch off or on, your problem is down on the ground some place. The horn wire in the basket has a dedicated power source you can "borrow" from if you need to for testing. Nice big 10ga wire
     
  3. TJK

    TJK Member

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    Jul 23, 2022
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    Location:
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    Thanks for the detailed procedure on how to center the valve for drive motors. Definitely going to try that after I get my voltage problem figured out.
     
  4. dbris

    dbris Active Member

    Joined:
    Mar 27, 2010
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    32
    Location:
    Los Angeles
    I haven't posted in a while because we haven't had any problems we couldn't handle. But now our 40F has lost the pulley from the accessory drive below the distributor, that drives the alternator, and it's gone. Can anyone give me the dimensions so I can get another one? It's the Wisconsin VG4D engine. Thanks.
     
  5. dbris

    dbris Active Member

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    Location:
    Los Angeles
    Did everyone go home? I really need some info on that pulley, we're dead in the water without it. Thanks.
     
  6. TJK

    TJK Member

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    Location:
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    Mine measures 3 1/2” outside dia
     
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  7. TJK

    TJK Member

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    Jul 23, 2022
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    Location:
    Indiana
    Also a 3/8” belt width
     
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  8. OFF

    OFF Senior Member

    Joined:
    Sep 30, 2009
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    950
    Occupation:
    HD Mechanic
    Location:
    Alberta, Canada
    I gave it my best shot back in July, but I couldn't find any mention of that pulley anywhere, JLG or Wisconsin. So I left it up to someone who still had a 40F to come to your rescue. Thank you TJK :)
     
  9. dbris

    dbris Active Member

    Joined:
    Mar 27, 2010
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    32
    Location:
    Los Angeles
    Thank you all, I really appreciate the help!
     
  10. Scooter.crew

    Scooter.crew Member

    Joined:
    Sep 24, 2022
    Messages:
    7
    Location:
    Maine
    Hello all. I am new to this forum and posted the following in a new thread. However, I probably should have posted here. I assume the 40F and 50F are pretty close to the same as far as the mechanics and electrics.

    I have a very used but well running JLG 50F with a Wisconsin gas motor that does not want to drive well. All boom movements up and down, etc work great just moving it requires me to tow it with my backhoe. The first problem is that it will not move up even the slightest incline. I know the high idle does not work or the drive switch. I even revved the throttle by hand while I had someone else in the bucket driving and did not make a difference so I suspect it is the valve that allows more pressure to the drive motors. I tried to download some schematics but they were too fuzzy to read. I bought a manual but who knows when it will actually get here. I imagine that once I have the proper diagrams, I can troubleshoot the electrical issues.

    The second issue is that one wheel will spin if not on completely flat ground. I have been told I can adjust some valves to get "posi-traction" to work but have no idea of what those adjustments should be.

    If anyone has any ideas or directions for these adjustments it would be greatly appreciated. I apologize if these issues have already been posted, I tries to search through this thread but didn't find exactly what I was looking for. Thanks in advance,

    Scott
     
  11. TJK

    TJK Member

    Joined:
    Jul 23, 2022
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    9
    Location:
    Indiana
    My 40f will spin too if not flat on ground. I swing the engine-counterweight side over drive wheels with boom in and it’s enough to keep drive wheels flat on ground.
     
  12. 1693TA

    1693TA Senior Member

    Joined:
    Feb 27, 2010
    Messages:
    1,173
    Occupation:
    FAA Radar Engineer, (Retired)
    Location:
    Farmington IL
    Drive wheels spinning on unlevel ground is very common with these. There are "overcenter", or "counterbalance" valves in the drive wheel circuit(s), but these are to be pressure adjusted adjusted equally. If maladjusted, they will give you fits.

    IMO, the first thing to do in any t/s is to ensure full hydraulic pressure is being developed in the system, and then isolating into non operational sections to "drill down" into problematic sections.
     
  13. OFF

    OFF Senior Member

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    Occupation:
    HD Mechanic
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    Yes, the 50F is a little larger version with a larger Wisconsin engine, but they share most systems with the 40F.

    I agree that probably the first thing to do is getting some hydraulic pressure readings and find out what's up. Getting your high engine/high drive working again would be a bonus too. These were never "off-road" machines btw.

    I can offer you a JLG 40F manual set, just message me with an email address, and I'll send it right out.
     
  14. Scooter.crew

    Scooter.crew Member

    Joined:
    Sep 24, 2022
    Messages:
    7
    Location:
    Maine
    Thanks, once I get the electrics working, I will check pressures. Is there a decent pressure gauge you could recommend? And I would assume there are test ports or something like that to check pressures?
     
  15. Scooter.crew

    Scooter.crew Member

    Joined:
    Sep 24, 2022
    Messages:
    7
    Location:
    Maine
    I did some quick voltage checks after bypassing the swing joystick with a toggle switch. (Going right was intermittent, toggle fixed that) I will try to rebuild the joystick at a later time. In any case there is only about 9.5 volts at the basket control. Obviously With over 100 ft of wire there will be a voltage drop. So my question, is in understanding the way the joysticks control the valves. Seems like it is just a potentiometer that will increase the voltage the further you push from center. So in regards to my drive problems, will this big of a voltage drop cause the valve not to open all the way, thus not sending enough power to the drive motors? Am I thinking about this the right way or am I missing something? Thanks.
     
  16. Scooter.crew

    Scooter.crew Member

    Joined:
    Sep 24, 2022
    Messages:
    7
    Location:
    Maine
    I have a question about the drive valves/solenoids if anyone knows. The machine stopped driving in one direction and I found a broken wire on the drive valve solenoid. To splice it, I had to remove the solenoid because the break was right next to the body. Fixed it replaced it and it worked but then it would not drive the other direction, this time broken ground wire. (I must have broken it when replacing the solenoid). Fixed it and not drive does not work at all. Solenoids are getting power. And when I push the pin in it will not work either. When I push the pin in on the swing and lift, those work. So is there something I could have screwed up when putting the solenoids back on? Something to block the hydraulic flow?
     
  17. OFF

    OFF Senior Member

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    950
    Occupation:
    HD Mechanic
    Location:
    Alberta, Canada
    well, two things commonly happen when taking those valves apart.
    1 - a small part you didn't notice gets flushed out with the oil flow
    2 - you get a piece of dirt/grit in there and it stops things from moving freely.

    do you know what brand of controllers (joysticks) your machine has?
     
  18. Scooter.crew

    Scooter.crew Member

    Joined:
    Sep 24, 2022
    Messages:
    7
    Location:
    Maine
    They are PQ controllers
     
  19. Scooter.crew

    Scooter.crew Member

    Joined:
    Sep 24, 2022
    Messages:
    7
    Location:
    Maine
    Thanks for the Racine Manual. When I took the solenoid off, I may have lost the poppet. There is a rubber piece at the end of the plunger. Would that encase the poppet or is the poppet in between that and the valve? If so, I may have lost it. I suppose I should have taken the whole valve and repaired it on the bench. Where might I get parts for it?
     
  20. DanD441972

    DanD441972 Member

    Joined:
    Nov 19, 2022
    Messages:
    6
    Location:
    Rensselaer Falls,ny
    I am working on a JLG 40 F, it has a Parker 3 spool valve. I am in need of a couple Electric actuators for this valve or parts to repair them. Parker part number on the actuators is 234912-23A
    Any help wood be much appreciated!!