The JLG 40F Boom Lift Dilemma

[Birk7]

First things first I'd like to thank Willie59 for the manual. I think it was written for my lift it was built in 1980. It has helped me find a lot of problems. Right now I'm working on a speed problem. The lift, swing and drive will not go into hi speed. There was and still is a problem with the dump valve associated with these valves but I don't know if that is my speed problem. Just to let everyone know my backround is Electrical/ electronics I'm not to good on the hydrolics. Any thoughts on this speed problem????
Thanks

 

[OFF]

First things first I'd like to thank Willie59 for the manual. I think it was written for my lift it was built in 1980. It has helped me find a lot of problems. Right now I'm working on a speed problem. The lift, swing and drive will not go into hi speed. There was and still is a problem with the dump valve associated with these valves but I don't know if that is my speed problem. Just to let everyone know my backround is Electrical/ electronics I'm not to good on the hydrolics. Any thoughts on this speed problem????
Thanks

You should have 2 toggles switches on your basket control, one is "high engine" the other is "high drive". High drive only effects the drive speed and will only function when the boon is below horizontal. It's your road gear. High engine adds approx. 1000 rpm to the engine speed, again only when the boom is below horizontal. you should be seeing approx. 1400 rpm on low, 2400 rpm on high. If you have no high, the circuit runs from the toggle switch, down the boom to the main control box and into the potter/broomfield relay. One leg of this relay runs up to the angle sensor on the rear of the boom. Originally this was a glass mercury switch. Very fragile and commonly broken.

The dump valves don't normally give a problem, what does act up is the 12 volt solenoids that control the dump valves. The are mounted to the cross member under the engine. You may not have even noticed them.

 

[Birk7]

OFF,
I have repaired the wiring to the dump solenoid and replaced the bad relay. The RPM increases but the movement speed does not. Somebody had been into the dump valve and now when you assemble it the needle is set into the port. As though the solenoid is on. I was hoping to find a breakdown on the dump valve to see what I am missing... Parts or knowledge?

 

[OFF]

Birk7, do you know if your lift/drive/swing valve bank is Racine or Bertea? Bertea has a big knob each end, Racine has little pins you can push to activate the function when on ground control. is the function speed slow whether you're on ground or basket? I have a Racine manual on PDF, but it's at work and I'm off today. I'll get it to you if you have racine.

 

[Birk7]

OFF, They are Bertea, Could you tell me the function of the dump valve and what might be the result of it not working.
thanks

 

[OFF]

OFF, They are Bertea, Could you tell me the function of the dump valve and what might be the result of it not working.
thanks

the dump valve......dumps the hydraulic flow & pressure from the pump. When you activate a function or step on the deadman switch, the dump valve closes and supplies pressure to the control valves. The rest of the time the dump valve is open & flow circulates back to the tank.
If it's leaking, you would see slow functions/low hydraulic pressure. Get a gauge on it, see what pressure you're running compared to the spec in the manual.

 

[Grovecomm]

Hello. I am trying to ID a machine I'm looking to purchase. I have photos. Could I send them to you to take a look at? I can't find a nameplate anywhere.

Thanks - Dean

 

[adamj]

hi guys I have been reading through this thread and have learned a lot I was wandering if I could get the wiring and hydraulic diagrams for my dads 40f I believe its the bertea the machine was given to him about 6 years ago we started to work on it then it got set to the side and left alone I don't know much about it but I know the boom raises and lowers and the basket tilts and the steering works (atleast tries the end of the ram broke its weld and isn't connected at the moment) but it wont telescope in or out spin either way or drive and he has decided to scrap it if we cant get it going

thanks adam

 

[Grovecomm]

I would love to get electric & hydraulic schematics for a 40F also. A service manual would be great too. Can anyone help me and adamj???

 

[OFF]

I would love to get electric & hydraulic schematics for a 40F also. A service manual would be great too. Can anyone help me and adamj???

Welcome. Yes, when you and Adamj get 3 posts it will open up the private message system and you can use it to send me an email address I can send the pdf files to.

 

[Grovecomm]

Thanks OFF. This should make my third post, I'm still trying to figure this Forum out.

 

[Grovecomm]

Can anyone tell me if this is a JLG 40F??

 

[adamj]

got to work on mine today found out that it had the racine valves but one of the main valves that come from the pump to the block of valves that controls the swing, telescope, and drive the solenoid wasn't getting enough voltage checked with a jumper wire and now everything seems to work on it

 

[adamj]

also found out that it weighs so much that it mars up and I got it stuck in the driveway and will have to have my dad help with the tractor to put it back in its parking place especially since I didn't get to weld the steering ram back so it doesn't steer

 

[Grovecomm]

It's been reported to that the 40F weighs either 12,500 or 14,500 pounds. Two people, two answers, I don't know if either is correct.

 

[OFF]

Yes, that's an early 40F, I'd say pre-1977

 

[RSIGuy]

I am new to posting but own a 1978 40F and have been reading regularly and felt I should respond to this post.
My lift has manual bucket swivel.

 

[willie59]

Welcome to HEF RSIGuy. :drinkup

 

[RSIGuy]

OFF, I'm new to the thread but have a mid 70's 40F and am in the process of re-wiring the machine but looking at all the systems while its down. What is the fix if you are out of room for adjustment on the brakes.
Also, big question is while doing a function test on the systems (auxiliary pump mode) one drive motor does not spin, I have both removed from the hub to check seals etc. which made it convenient to do the electrical test but we're scratching on head why one one motor spins. Any help would be appreciated. BTw Racine valves on mine. Thanks.

 

[RSIGuy]

Thanks for the welcome! I have been learning a lot form you OFF and numerous others over the months just reading the thread. Quick question if your still on, I know I saw it somewhere in here but running out of time to review all the posts do you know what the two side by side valves (Racine) exactly do mounted up on top. We have the others mapped and labeled but confused on them believe they are high drive?