I am also looking for help on a JLG----60G. First I want to thank you guys for sharing you knowledge and keeping this old equipment running. My problem is when I step on the foot switch and not touching anything else it will take off in one direction, always goes the same way. Then it will go for a couple of hours and work perfect? It has the PLC brand controls. Thanks
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The JLG 40F Boom Lift Dilemma
- Thread starter od1
- Start date
willie59
Administrator
I haven't worked on a 60G myself, not sure how the differ from the F model machine or what components they use. Did you mean to say it uses PQ controllers? Also, when you say "it will take off in one direction", does that mean it swings in one direction, or booms up in one direction? Have you tried disconnecting the controller at the platform for the faulty function and see if that makes problem go away? Some pics of machine and components would help as I have never been around one.
Willie yes a PQ 120 series, hope this is correct I will check for sure tomorrow. It is the ground travel that takes off. I looked into unplugging the controller ,someone has cut out the plug and but spliced. So i need to get some sort of plug together splices. Willie I will get pictures, thanks
OFF
Senior Member
Welcome 225! I've never seen a 60G either but I'd sure like to. Love to see a picture of it 
Another way to tell what's up is to put the machine on ground control. If it still takes off on you, then it might not be controller. You'll need to "center" the valve spool for that function. Controller is the most common cause though.
Another way to tell what's up is to put the machine on ground control. If it still takes off on you, then it might not be controller. You'll need to "center" the valve spool for that function. Controller is the most common cause though.
VoodooMojo
Senior Member
The G models weren't that much different than the F.
It was a change-over model between the F and the H. Arguably the best models built. The G, not so much. It was not around long.
Cosmetic difference was the engine cover was a slide-back canopy that was a real pain in the ass.
Another issue was what might be causing this problem.
If the function that is taking off is one of the proportional functions it may be from the pilot section of one of the control valves.
The majority of the G models used the Bertea valve bank.
The pilot sections of these valves were very sensitive and could act up, especially in cold weather.
Back during the day, in the winter in Illinois, Wisconsin, Minnesota etc, the machines would have to be started and left running for about an hour or so before the oil was thin enough to flow smoothly through the pilot section.
Thet were notorious for sticking or just plain not working at all.
The pilot sections are interchageable between the different functions so troubleshooting wasn't too difficult, just messy.
The ones with Racine Proportional Valves were a bit better.
I should have the manuals for the G. I will look in the shop tomorrow morning.
You can swap the wires from the drive valves to the lift valves to see if the problem follows the controller /wiring or the hydraulics/valves.
Some more info is necessary.
It was a change-over model between the F and the H. Arguably the best models built. The G, not so much. It was not around long.
Cosmetic difference was the engine cover was a slide-back canopy that was a real pain in the ass.
Another issue was what might be causing this problem.
If the function that is taking off is one of the proportional functions it may be from the pilot section of one of the control valves.
The majority of the G models used the Bertea valve bank.
The pilot sections of these valves were very sensitive and could act up, especially in cold weather.
Back during the day, in the winter in Illinois, Wisconsin, Minnesota etc, the machines would have to be started and left running for about an hour or so before the oil was thin enough to flow smoothly through the pilot section.
Thet were notorious for sticking or just plain not working at all.
The pilot sections are interchageable between the different functions so troubleshooting wasn't too difficult, just messy.
The ones with Racine Proportional Valves were a bit better.
I should have the manuals for the G. I will look in the shop tomorrow morning.
You can swap the wires from the drive valves to the lift valves to see if the problem follows the controller /wiring or the hydraulics/valves.
Some more info is necessary.
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pictures of 60G
I will try to post pictures of my JLG. To review my problem. When you push the foot peddle, sometimes the ground travel will be active and the machine will start to travel without touching anything but the foot switch. What would be the problem? Thanks for your help.
If you need more pictures, just let me know what.
View attachment 87765
I will try to post pictures of my JLG. To review my problem. When you push the foot peddle, sometimes the ground travel will be active and the machine will start to travel without touching anything but the foot switch. What would be the problem? Thanks for your help.
If you need more pictures, just let me know what.
View attachment 87765Attachments
OFF
Senior Member
Good to see you've got Racine proprtional valves. That's a bonus. I was surprized to see it powered by a Wisconsin engine though. Thanks for the putting up the pics.
As Willie59 said, first step is to disconnect the drive controller and see if it still does the "auto-drive" trick.
As Willie59 said, first step is to disconnect the drive controller and see if it still does the "auto-drive" trick.
VoodooMojo
Senior Member
there is a valve bank on the other side, do you have a photo of that?
VoodooMojo
Senior Member
Here is the Drive section of the Valve Assembly
The easiest way to determine if it is an Electric or Hydraulic issue is to
reverse the coil wires (+ and -) at the Drive Valve.
If the problem continues to stay in the same direction, then a hydraulic problem could be assumed.
If the problem changes directions, then an electric problem could be assumed.
Swapping the wires from the lift coil (the valve immediately next to the Drive Valve) to the drive coil and vice versa, will also be an easy test. If the problem stays with the Drive controller, then the problem is in the Drive Controller circuit and not the Drive Valve (in effect, if after making this swap, the lift function, and not the drive, starts taking off by itself).
If the problem stays with the Drive Valve, then the Drive Controller circuit (except for the coils) would not be suspect and there would be a possibility of drive valve coil or valve component issues.
The easiest way to determine if it is an Electric or Hydraulic issue is to
reverse the coil wires (+ and -) at the Drive Valve.
If the problem continues to stay in the same direction, then a hydraulic problem could be assumed.
If the problem changes directions, then an electric problem could be assumed.
Swapping the wires from the lift coil (the valve immediately next to the Drive Valve) to the drive coil and vice versa, will also be an easy test. If the problem stays with the Drive controller, then the problem is in the Drive Controller circuit and not the Drive Valve (in effect, if after making this swap, the lift function, and not the drive, starts taking off by itself).
If the problem stays with the Drive Valve, then the Drive Controller circuit (except for the coils) would not be suspect and there would be a possibility of drive valve coil or valve component issues.
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JLG 40f help needed
Greetings from Finland to all Forum members. I am a new member and I have not yet had time to read the whole thread just pieces here and there. Lots of good information thank you very much. a week ago I bought an old JLG 40f boom lift. I do not even know the model year. I tried to compare the auction sold lifts serial numbers but they were generally 7xx xxx my own is 52 360 and made in the United Kingdom? I have many problems which needed a help. part of the electrical cables must be changed, repair hydraulic valves and brakes. Hydraulic system has a fault when you use the lift up or other levers the machine is moving slowly backwards I guess that the o rings in valve blocks are broken? In addition i need for electrical and hydraulic circuit diagram. I am also interested of all kind manuals. here in Finland today is-30C (-22F), so it's nice to stay inside.
forgive my terrible English, this is partly translated into online translator
Greetings from Finland to all Forum members. I am a new member and I have not yet had time to read the whole thread just pieces here and there. Lots of good information thank you very much. a week ago I bought an old JLG 40f boom lift. I do not even know the model year. I tried to compare the auction sold lifts serial numbers but they were generally 7xx xxx my own is 52 360 and made in the United Kingdom? I have many problems which needed a help. part of the electrical cables must be changed, repair hydraulic valves and brakes. Hydraulic system has a fault when you use the lift up or other levers the machine is moving slowly backwards I guess that the o rings in valve blocks are broken? In addition i need for electrical and hydraulic circuit diagram. I am also interested of all kind manuals. here in Finland today is-30C (-22F), so it's nice to stay inside.
forgive my terrible English, this is partly translated into online translator
willie59
Administrator
Welcome to the forum peters. :usa
Your English translator is working well, we can understand what you're writing. We need to know if your machine has Bertea or Racine proportional control valves, and if it uses PQ controllers at platform or Cutler Hammer.
You need to make 3 posts to the forum, then your member status will be changed to Junior Member, then you can send me your email address via private message. I can then forward some information to you via email.
Your English translator is working well, we can understand what you're writing. We need to know if your machine has Bertea or Racine proportional control valves, and if it uses PQ controllers at platform or Cutler Hammer.
You need to make 3 posts to the forum, then your member status will be changed to Junior Member, then you can send me your email address via private message. I can then forward some information to you via email.
willie59
Administrator
Post #31 shows the different platform contollers used on the 40F for proportional controls. Post #35 shows a Bertea proportional control valve, it has the manual control knobs on it. Post #225, first picture, to the left of hour meter, shows a Racine proportional control valve.
OFF
Senior Member
For peters & 225 - once you've determined that your JLG moving on you when using other controls is NOT an electrical issue........you need to set your null. (center your pilot valves) Refer to post #591 by Voodoomojo - he's marked in red where the null adjustment is on your racine proportional valves. As he points out, drive is the valve section with the large hoses on it. Swing has the built-in pressure reliefs, lift is the other one. The null adustment is on the bottom of the valve, a set screw with a 1/2" (13mm) lock nut on it.
Block the wheels. With the engine running on ground control, turn the set screw inward until you hear the hydraulics change tone (the function begins to activate). then turn the set screw out until you hear the tone change again (function begins to activate the other direction). Note the turns or turn it took to get from one direction to the other. Turn the set screw to the middle point and lock it down.
Block the wheels. With the engine running on ground control, turn the set screw inward until you hear the hydraulics change tone (the function begins to activate). then turn the set screw out until you hear the tone change again (function begins to activate the other direction). Note the turns or turn it took to get from one direction to the other. Turn the set screw to the middle point and lock it down.