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1999 JLG 450A with a drive problem

Discussion in 'Forklifts/Telehandlers' started by davis1676, Sep 28, 2012.

  1. davis1676

    davis1676 Well-Known Member

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    Hey Guys! I was searching online for information on a lift I bought and your site came up and it looks like you guys have gotten your hands dirty just a few times. :) I found this lift and it had been sitting up for about three years with a drive problem. I have rebuilt the zenith carb, replaced the alternator ( that was fun ) battery, flushed radiator and changed out the oil and filter. I got to the hydraulic tank and it had a bent area on top of the tank and the flange cover ( fill cap area ) was cracked open so rain could go right on in the hydraulic oil. I pulled flange and looked in the tank and to my amazement there was no rust but oil was as milky as it could get. Drained the oil and replaced with fresh oil and drained hydraulic lines best I could. Cranked that little jewel up and ran like a charm. I now am stumbling over the hydraulics with this thing and want to get the forward and reverse working and would like a little help anyone feel like helping me with a few questions. I need to pick someones ear.
     
  2. barklee

    barklee Senior Member

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    What is the machine not doing? Anything? Can you be more descriptive? Thanks
     
  3. davis1676

    davis1676 Well-Known Member

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    Thanks for answering my post. This thing is hard to fix without some direction. I changed out the hydraulic fluid because water was in it and knew when I got it the complaint was that it would not move forward or reverse. I tried the forward and reverse and the machine would move back and forth about six inches. I jacked up the drive wheels and tried again and the wheels turn together and then one quit responding and now the other wont turn. I worked all day today looking for the problem and just dont see it. All other hydraulics work fine seem fairly strong. My question first off is where are the drive motors getting energized from I cant find the valve location in the manual that was online at the JLG site. I have taken some pictures if I can fiqure out how to get them on here.
     
  4. davis1676

    davis1676 Well-Known Member

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    looks like I cant post pics yet but I could email them. thanks for any help.
     
  5. VoodooMojo

    VoodooMojo Senior Member

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    The drive valve is located on the drive pump. It is controlled by the drive control card in the upper control box.

    Outputs A and B of the Control Card run directly (not counting a few connections along the way) to the Drive Pump that is bolted to the engine bell-housing.
    There is a valve located on the drive pump. It is called an EDC. Electric Displacement Control. There should be a couple of Orange wires connected to it. Orange wire # 7-2 is the Forward signal from the control card and Orange wire # 8-2 is the Reverse signal wire. The Orange wires 7-2 and 8-2 change to Brown/Red and Brown/Blue at the connector plug. The Brown/Red and Brown/Blue run up the booms to the Upper Control Box where they change back into Orange wires 7-1 and 8-1 where they are connected to Outputs B and A.
    Output X on the Control Card is used for Brake Release.

    Most of these machines used the M46 Sundstrand-Sauer pump. The EDC of this pump is mounted directly to the pump. It will have a small override lever attached to it. If you have trouble finding it, just follow the wires leading to the pump.
    With the brakes released, moving the lever in one direction or the other will cause the machine to drive in the corresponding direction.
    To release the brakes, you will have to jumper 12 volts to the brake release coil. Be sure the machine is on level surface or the drive wheels are raised off the ground when the brake coil is jumpered as the brakes will be fully released when the engine is started.

    If another type pump is installed on the machine it will have two separate coils. One is the Forward coil and the other is the Reverse coil.

    Either way, we can check for voltage at the inputs to the pump on the orange wires.

    At least then we will be able to determine if it is an electric problem or a hydraulic issue.
     
  6. davis1676

    davis1676 Well-Known Member

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    thanks for your help VoodooMojo sounds like you been around these machines. I will check that out soon as this rain lets up. I do have it on level ground in front of my shop.
     
  7. davis1676

    davis1676 Well-Known Member

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    here are a few pics of what we dealing with
    pump section 2.jpg pump section.jpg distribution block.jpg
     
  8. barklee

    barklee Senior Member

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    I have a 400S that is doing the exact same thing. It is the Rex Roth drive card located under the control box lid thats causing the problem. Try to swap the connections for the next card over, they are all the same card. If your drive works (like mine did) than you know thats the problem
     
  9. davis1676

    davis1676 Well-Known Member

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    10-4 I will try that also. thanks for your reply barklee
     
  10. davis1676

    davis1676 Well-Known Member

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    Ok, I took the cover off of the EDC and connected my voltmeter to the pins on the inside of the switch. I didnt know there was oil in there ( oops ). What kind of oil goes back in there? I switched over to the platform control and kicked joystick into forward and tied it off. ( I do have the drive wheels off the ground ) I checked the brake solenoid with a piece of metal to make sure it was energized and checked voltage on red and black wires. I got 56.7 milivolts and when I release the joystick back to neutral it went back to 0. I checked reverse and if I was checking it right I got 24.3 milivolts and it also returned to zero when I released it. I tried to manually switch the EDC to forward and reverse with the small plastic lever and it moved back and forth but felt like it was not moving anything behind the switch. I took that cover off and seen what the plastic lever moved, it had a spring on both sides and I tried by hand to move it back and forth but it would not move. So I put it all back together. Should that EDC manual control move with the machine off or does that have to have charge pressure? Seems like its stuck because I could not move the controller by hand when I took it apart.
    manual drive switch.jpg lever EDC.jpg
     
  11. VoodooMojo

    VoodooMojo Senior Member

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    That will be a transformer (silicone) oil in the EDC. Grainger will have it.
    I should have made it clear to measure the voltage at the plug a few inches from the EDC.
    Try not to energize the EDC for a great length of time without the oil in it.

    The lever should move freely. It must be bound up.
    Being froze-up may have caused the control card to be damaged.

    The identification tag will have a number on it.
    Check the list in this datasheet for the number on the tag:

    http://www.sauer-danfoss.com/stelle.../documents/product_literature/bln-95-9061.pdf

    Look for your number for some info.
    resistance, current, etc.
    If your EDC number is not on the list, search the Sauer-Danfoss site to find it.
    It may com in handy.

    If we would have found low or no voltage at the coil, the next step would be as barklee said, check the input voltage and the A and B outputs at the control card in the upper control box.
     
  12. davis1676

    davis1676 Well-Known Member

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    thanks for the link. I have been reading up on the EDC and the pump. I am going to order myself some gauges so I can test pressures and also take out what check valves,ect from the pump ( one at a time ) according to the pump information and see if any have torn O rings or broke springs or maybe just stuck. I will also ohm out the EDC transformer to make sure its good. Any other things come to mind let me know. I will let you know of my progress.
     
  13. davis1676

    davis1676 Well-Known Member

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    well I got some hoses and gauges and tested the drive pump best I could. I really wasnt making much headway so I got frustrated and called Darr Equipment they are suppose to be the service rep for JLG around here. They showed up at 8 oclock this morning and we cranked up the machine and he tried to get it to move and it didnt so he took down the serial number and model and said he would have to get some information on it. Should this dude be very familiar with a series 40 M64 drive pump? I thought this was a very common drive pump and the 450A is not new but I still see alot of them around.
     
  14. VoodooMojo

    VoodooMojo Senior Member

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    Did you get the override lever to move?

    The M46 pump was/is used on a good percentage of all brands of aerial work platforms.
     
  15. davis1676

    davis1676 Well-Known Member

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    no, I didnt get no response from it. I talked to a man that until last year has worked on alot of the M46 pumps and he is going to come over and look it over with me. He told me to get a new 10 micron charge filter ( on order ) and take the old one and put it in a vise and squish it then cut it open and look for metal and then we will go from there. While I am waiting on some parts I ordered, I have been working on a electrical problem. Everything works from the platform with the exception of the lift up. Lift down works and levels out the platform and then descends. lift up works from ground control but when you try lift up the lift card has a small red light on it and it will blink and go off. I can perform lift down and the red light stays on on the control card and works like it should. I switched out the swing card with the lift card and the swing card did the same thing. I traced the lift wire 3-1 down to the ground control and the wire is good. Got any ideals. I have looked this schematic over and just dont see it.
     
  16. davis1676

    davis1676 Well-Known Member

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    Here is a few pics under the platform control. platform lift problem1.jpg platform lift problem2.jpg platform lift problem3.jpg
     
  17. willie59

    willie59 Super Moderator

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    Could be a faulty micro switch in boom up/dwn controller, sending faulty info to the proportional circuit card for boom control.
     
  18. davis1676

    davis1676 Well-Known Member

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    I switched the joystick up and down for the swing left and right and the swing was working good off the up and down of the joystick and the up function still would not work. I hope that made sense. How about a bad diode?
     
  19. VoodooMojo

    VoodooMojo Senior Member

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    is there voltage present at the Lift UP valve when the Joystick is stroked? If so, how much?
     
    Last edited: Oct 5, 2012
  20. davis1676

    davis1676 Well-Known Member

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    thats a very good question and I will let you know tomorrow. I didnt think about that since the lift function works at the ground. My head had me thinking platform down problem. Thanks for the nudge.