The JLG 40F Boom Lift Dilemma

[modern]

Jlg40fr

If there is anyone that has electrical and hydraulic schematics, it would sure be appreciated if we coulc get a copy either emailed, faxed or snail mail. Let me know. My mechanics have been scratching their heads the past few days.

 

[OFF]

If there is anyone that has electrical and hydraulic schematics, it would sure be appreciated if we coulc get a copy either emailed, faxed or snail mail. Let me know. My mechanics have been scratching their heads the past few days.

I've never seen a 40FR but I can email you the 40F schematics I have.
How many toggle switchs for high drive? One or two? (not counting high engine)

I'm trying to get the 40F manual scanned in to an emailable format for EMT,
when I'm successfull I'll can send you a copy too.

 

[modern]

Jlg 40fr

We have one toggle switch for high drive. They are still under the hood when I asked them. Any help would be greatly appreciated. thank you,

 

[EMT]

Well Finally figured it alll out.Man talk about brain damage!
the hyd oil is contaminated from the hyd pump taking a dump. So particles in the oil reservoir causing the dump valve to stick open sometimes or stay closed sometimes. Then the wiring harness is soooooooooo old and funky that the voltage reading is less when unit is cold(right now in denver it like 30's) then when unit warms up the voltage is more (this is at the control valves). So it would start out at 7 or 8 volts at control valves in the morning then we would shut off unit and return in the middle of the day when it gets the warmest the voltage is now 11 or 12v. All the time the alternator it is putting out 13.6 volts......... CRAZY OLD AND FUNKY.
Thanks for your help in the jlg 40f delima

 

[willie59]

Well Finally figured it alll out.Man talk about brain damage!
the hyd oil is contaminated from the hyd pump taking a dump. So particles in the oil reservoir causing the dump valve to stick open sometimes or stay closed sometimes. Then the wiring harness is soooooooooo old and funky that the voltage reading is less when unit is cold(right now in denver it like 30's) then when unit warms up the voltage is more (this is at the control valves). So it would start out at 7 or 8 volts at control valves in the morning then we would shut off unit and return in the middle of the day when it gets the warmest the voltage is now 11 or 12v. All the time the alternator it is putting out 13.6 volts......... CRAZY OLD AND FUNKY.
Thanks for your help in the jlg 40f delima

Yep, seen fragments and debris get lodged in valves before, all sorts of goofy things can happen. Glad to hear ya got it working.

Hey OFF, I have the wiring PDF's for the 40F that I should be able to email to modern if you don't come up with something.

 

[OFF]

Hey OFF, I have the wiring PDF's for the 40F that I should be able to email to modern if you don't come up with something.

Hey thanks, but I sent him the 40F schematic set a while ago.
Amazing how many of those machines are still out there working.

I googled a 40FR, looks just like a 40F to me :beatsme

 

[willie59]

Hey thanks, but I sent him the 40F schematic set a while ago.
Amazing how many of those machines are still out there working.

I googled a 40FR, looks just like a 40F to me :beatsme

LoL, yeah, I was talking to od1 one day and he said the same thing about how many of these things are still out there. I told him that I have a feeling this thread is going to live as long as the 40F.

Hey modern, have you located the hi-drive solenoid valve? Have you tried connecting power and ground to solenoid valve with jumper wires to see if it activates hi-drive? That's where I would start.

 

[Tim_]

I've been following the discussion on JLG 40F because I have one. Everything has been working well except today after using it to trim a tree for about 2hrs and driving back into the shop area I lost my steering, boom in/out, and basket tilt. I tried form both positions and same story. It just quit working all of a sudden. Also could someone please E-mail me a set of schematics. I printed the ones on the forum but couldn't make them out when I enlarged them. Thanks Tim_

 

[OFF]

I've been following the discussion on JLG 40F because I have one. Everything has been working well except today after using it to trim a tree for about 2hrs and driving back into the shop area I lost my steering, boom in/out, and basket tilt. I tried form both positions and same story. It just quit working all of a sudden. Also could someone please E-mail me a set of schematics. I printed the ones on the forum but couldn't make them out when I enlarged them. Thanks Tim_

Sounds like you lost one of the solenoid valve banks. Locate the dump valve for that bank, check the ground wire on it, then look down on the frame beside engine or on the crossmember under the engine for a relay (solenoid) that controls that dump valve. Chances are it's one of those two things.
If your profile lists an email I'll send you schematics.

 

[Tim_]

Hey thanks OFF, I just checked my E-Mail and I got the stuff you sent. Let me mull this over now that I know what I'm looking at and I'll let you know what I find. Thanks agian, Tim_

 

[OFF]

Hey thanks OFF, I just checked my E-Mail and I got the stuff you sent. Let me mull this over now that I know what I'm looking at and I'll let you know what I find. Thanks agian, Tim_

And Welcome to the site

 

[Tim_]

Are there any pictures of the valve banks that indicate there function ie. boom in/out. Also are there any hydraulic diagrams available? On an earlier post I saw a picture of valve bank called the "bang-bang valves with the dump valve at the top. My machine has Racine valves but not sure whats what without actually tracing out the wiring. Thanks to OFF I now have a good set of wiring schematics. I have limited experience in valve blocks and was wondering what the dump valve actually does? Tim_

 

[OFF]

Are there any pictures of the valve banks that indicate there function ie. boom in/out. Also are there any hydraulic diagrams available? On an earlier post I saw a picture of valve bank called the "bang-bang valves with the dump valve at the top. My machine has Racine valves but not sure whats what without actually tracing out the wiring. Thanks to OFF I now have a good set of wiring schematics. I have limited experience in valve blocks and was wondering what the dump valve actually does? Tim_

Yes, you're looking for a bank of 3 bang-bang valves (also called solenoid valves). I believe there are 2 such banks on a 40F. The dump valve controls the oil flow to the valve section (like an off/on switch) and it sort of looks like 1/2 a bang-bang. Some are mounted right to the bang-bang section, others are remotely mounted.
As for which valve does what, even the manual isn't reliable on that. Only way I know of is to pull one spade connector at a time on the bang-bangs and note which function stops working. Then mark them so you know for next time.
According to the schematic, follow the hose connected to the middle pump section. It should lead directly to the dump valve you're after.

 

[willie59]

I have limited experience in valve blocks and was wondering what the dump valve actually does? Tim_

Hi Tim,
Looks like OFF has pretty much got you taken care of, and I have only worked on 40F's with Bertea valves, he knows much more about the Racine set ups on this machine. But I can answer your question about the purpose of the dump valve. The dump valve does what the name implies, it dumps oil back to the hyd tank. JLG didn't want pressure and flow going to the valve bodies when no functions are being operated. When you have the engine running, and your not working anything, the dump valve sends the oil supply to tank. When you operate a function of that valve bank, your doing two things; 1) you power up the dump valve coil, which now diverts the oil to the valve body, and 2) you power up the coil of the valve function your operating, like telescope out. When you let go of the telescope out function, the telescope valve centers itself, and the dump valve now diverts oil to tank. Of the number of benefits of using a dump valve, one would be the scenario we just described. Let's say your telescoping out, let go of the telescope toggle, but the telescope valve malfunctions, and it continues to boom out. You could be telescoping into a wall or something and unable to stop it. The dump valve provides a redundant back up in this case. Telescope valve malfunctions, but the dump valve still operates, sends oil to tank, telescope stops. Hope that helps you out a bit.

 

[Tim_]

Thanks for the input now all I have to do is get a little time to really dig in to this beast. Oh also can you manually operate the valves by pushing in on the pin coming out of the coil. I guess I'd have to do the dump valve and the function valve both if possible. Just a thought. Tim_

 

[willie59]

Yep, that's the way they work. Rather stiff to push those pins in. And yes, dump valve has to be pushed in as well to operate a function. If you had a machine that lost electrical controls, but engine still ran, you could manually operate boom this way.

 

[dbris]

I just stumbled across this forum and you guys have answered a LOT of my questions already. I have a 40F that has suffered many years of maintenance abuse by people that knew very little about electrical stuff, and as a result, very little of it worked. I have the task of making it serviceable but I have no electrical or hydraulic schematics to work with. I've spent a lot of time reverse engineering and I think that my drawings are pretty close but still have a few issues, hi drive being one of them. I wonder if it would be possible to get ahold of some real schematics? I believe we have the Racine controllers. Thanks for all the help you folks have been already!

 

[willie59]

Welcome to the forum dbris. :usa

I've got electrical schematics for Racine and Bertea valves that OFF sent me. I can email them to you if you know which ones you have. Is that your preferred email address you have at your member profile?

 

[dbris]

Yep, that's a good email address and thanks for the help, I can't wait to see how wrong my drawings are!

 

[willie59]

Yep, that's a good email address and thanks for the help, I can't wait to see how wrong my drawings are!

You got mail!

BTW, you need to make another post and you'll become a Junior Member.