The JLG 40F Boom Lift Dilemma

[mike terrigno]

Know the choke solenoid is broke I have manually have to choke it but when it's running and it shuts off I never have to choke it after that it should just start a usually starts right up that's that's why I'm thinking it's a safety issue because if I if I depress the foot safety switch it automatically kills the motor

 

[mike terrigno]

I can get in the machine right now get in the platform and operate it for about a half hour then then all the sudden it shuts off

 

[tool_king]

I had one do the same thing .It was the timer relays in the upper control box .They are black and mounted on the far right corner of the
box .Replace them both .When you do .Do the one at a time replacing the wires so you don't get messed up .

 

[mike terrigno]

Upper control box can you explain where alittle better . Is in the the platform or engine compartment

 

[mike terrigno]

There are 2boxes in the engine compartment

 

[tool_king]

There are 2boxes in the engine compartment

Hi Mike
It is in the upper control box in the basket .When you open the box it will be under were your drive joystick .They tucked up in the right corner . If need call me on my cell 908-305-8457.
thanks
Ed

 

[mike terrigno]

Ed when I get home I will text you a few pictures if that's ok

 

[tool_king]

sounds good

 

[mike terrigno]

My controls

 

[OFF]

When I'm up in the platform working the machine runs fine then all the sudden shuts off will not restart from platform the motor just turns over I can't seem to find out if it's the solenoid or some safety switch that needs to be replaced from the ground everything works will start right up if I wait a half-hour sometimes I can get in the platform and it'll start right back up

Hi Mike, I can't think of anything in the ignition circuit that would cause what you're describing. They are pretty basic, just point to point wiring with nothing in between but connections. First thing I would do is check for proper voltage at the positive terminal of the ignition coil, both when the engine is running normally and after it quits and won't restart. Look for hot spots that mean high resistance on connections and toggle switches. If you're voltage is staying good, you might have an engine type problem.

 

[mike terrigno]

Thanks for the help guys still tring to diagnose the problem keep me in mind if you guys think of anything

 

[Sylvana]

Hello, I am new to this forum and I have recently purchased a JLG 40F Boom lift, I am having a very hard time finding a service manual for this machine, hopefully someone can help me, thanks in advance!

 

[John D.]

Hi everyone, It seems that it is next to impossible to find a manual for a JLG 40F. IF some one has one, could you please send me one. Thank You

 

[OFF]

Hi everyone, It seems that it is next to impossible to find a manual for a JLG 40F. IF some one has one, could you please send me one. Thank You

I got you John D. Check your PM's.

 

[Glbuilders]

I have a JLG 40F and it is leaking hydraulic fluid out of the telescoping tubes, any where I can get a repair manual for it? I have a feeling it’s one of the connections or a seal goin bad. Also trying to figure out how to pull the cylinder out. Any help would be appreciated.

 

[OFF]

I have a JLG 40F and it is leaking hydraulic fluid out of the telescoping tubes, any where I can get a repair manual for it? I have a feeling it’s one of the connections or a seal goin bad. Also trying to figure out how to pull the cylinder out. Any help would be appreciated.

Welcome Glbuilders! Just use the private message function to send me an email address you would the manuals in PDF format sent to, and I'll get right on it.

I believe all the connections for the telescope cylinder are located on the very rear face of the cylinder. Take the cover off the back of the boom (3 small bolts) and you should be able to see if it is leaking from one of those connections. Hopefully it is, that's the easiest fix possible. Also check the basket slave leveling cylinder mounted on the top of the basket end of the boom. Your leak may be there also. There is a procedure in the service manual for removing the telescope cylinder if it comes down to that. Good luck

 

[Shredon]

Just wanted to put a BIG thanks out to OFF and willy59 for their continued help in this thread.
OFF has informed me the main shaft seal on the hydraulic pump for my 1979 JLG 40FR is a C/R 9878

 

[OFF]

Just wanted to put a BIG thanks out to OFF and willy59 for their continued help in this thread.
OFF has informed me the main shaft seal on the hydraulic pump for my 1979 JLG 40FR is a C/R 9878

Thank you Shredon, it's been a pleasure helping you. And a big thanks to the Heavy Equipment Forum for giving us a place to get together like this. And od1, the member who started this topic/thread.
Sharing ideas and information - the good side of the internet.
That seal information actually came from another member who hasn't posted yet but has been in contact though the PM system.

Dave the shaft seal is C/R 9878. My travel motors are parker M2H25412S42NB-8003901SPCL SERAL NO. JO4K003 Terry

Additional thanks to Shredon for converting the PDF manuals we've been sending out to a newer format that is searchable and take up way less space. Each section is now 2mb or less instead of 6mb+

 

[D 40G]

Hey all. I am a newbie needing help with a 1984 JLG 40G I have owned for 20 years and kept going. I have the parts manual and maintenance manual. It doesnt have any good electrical troubleshooting or even electrical parts layout and identification. I have a problem mentioned by Senior member OFF back in 2013. The lift wont swing, lift, or drive from either the basket or ground controls. OFF said check the dump valve solenoids near the engine on a 40F model. Mine has relays that look like a Ford starter solenoid. Some behind the engine and a couple near the Racine valves. Can anyone suggest where and how to check the solenoids and which one it would be? I Would like to have a decent schematic to follow if anyone can help. I have tried the 40H wiring diagrams but they are different. Any parts layout diagrams in existence? It would be nice to know where each electrical part is and its function. I have always fixed every problem in 20 years but I dont have enough info to fix the drive, swing, and lift issue. Also I am a bit ignorant of what a dump valve is and does. The second story roof on the house is off and it is raining every day. Please help anybody

 

[OFF]

Hi D 40G, as a person has removed the roof and added a second story while still living in the house.....I understand what rain means.

Those solenoids I mentioned do look like Ford starter solenoids, only they are silver in color. Quickest way to make it work? Take a good sized jumper wire with alligator clips on it and connect the large terminals of each solenoid, one solenoid at a time. One will blow the horn, one will make the aux. pump kick in, one will make your lift/swing/drive work, the other will make your telescope/steer/level work. There may be others for things like an electric choke. Once you've identified each solenoids function, you can pin point the one you're having a problem with. You can operate the 40G with the jumper in place, just remove it when you shut down or it will drain your battery.
On ground control - you should have power to one of the large terminals and to one of the small terminals. There may only be one small terminal. If it's got two small terminals, the other one is grounded.

What this solenoid is doing is powering the dump valve for the proportional valve bank. A dump valve dumps the hydraulic flow/pressure when you are not using any functions. On basket control, the dump valve is operated with the foot switch. On ground, it is powered whenever the ignition is on.