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The JLG 40F Boom Lift Dilemma

Nige40F

Member
Joined
Jun 19, 2022
Messages
16
Location
UK
What a mine of information on here so thankyou to all who have posted in the past.
Ive just started looking after one so may have some questions (hopefully not stupid ones) but its not in the best condition but somewhat re-purposed :)


Very much looking forward though.



jlg5
 

OFF

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Sep 30, 2009
Messages
1,047
Location
Alberta, Canada
Occupation
HD Mechanic
What a mine of information on here so thankyou to all who have posted in the past.
Ive just started looking after one so may have some questions (hopefully not stupid ones) but its not in the best condition but somewhat re-purposed :)


Very much looking forward though.


Welcome to the Forum! I look forward to helping with any problems you may have.
 

Nige40F

Member
Joined
Jun 19, 2022
Messages
16
Location
UK
Welcome to the Forum! I look forward to helping with any problems you may have.

Thank you kind sir and my immediate question if i may is were they all made with diesel engines and any idea of manufacturer (cant find anything on it)?


Many thanks
 

OFF

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Alberta, Canada
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HD Mechanic
Thank you kind sir and my immediate question if i may is were they all made with diesel engines and any idea of manufacturer (cant find anything on it)?


Many thanks

To my knowledge, the 40F only came with one engine. It was a Wisconsin VH4D, and air cooled, V-4, 30HP gasoline engine.
I'm sure we'd all be very interested in what diesel engine you have in your 40F. Must be air cooled, right?
In later models, JLG commonly used the Deutz F3L912 or F3L1011 or F2L511.
 

Nige40F

Member
Joined
Jun 19, 2022
Messages
16
Location
UK
It is indeed sir cooled sir and not something I have seen before.

thanks for the tips on the Deutz engines and I’ll have a look
 

Nige40F

Member
Joined
Jun 19, 2022
Messages
16
Location
UK
I suspect it will sir and will do so when next up there which will be tomorrow evening.

Big job I’m guessing is the retract chain has snapped (at least I gather that is what it is for and does look a bit challenging).

very much appreciate your interest and help and advice though sir that is for sure.
 

OFF

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Alberta, Canada
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I'd be happy to email you a set of manuals for your 40F in PDF format. Just message me with an email address.
 

Nige40F

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Joined
Jun 19, 2022
Messages
16
Location
UK

OFF

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Sep 30, 2009
Messages
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Alberta, Canada
Occupation
HD Mechanic
The first diesel JLG 40F I have ever seen! Thank you for the picture. Very nice engine to have in there.
 

Nige40F

Member
Joined
Jun 19, 2022
Messages
16
Location
UK
Thankyou sir,

It can be a bit of a bugger to start on a cold morning but is indeed a bonny wee thing.

That said its better with the leak repaired on one of the delivery valves and appears quite robust (of which in the hands of our people needs to be lol).
 

TJK

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Joined
Jul 23, 2022
Messages
9
Location
Indiana
Hi everyone just came across this forum while searching for manuals for my 40f. First I want to say thanks to everyone sharing their time and knowledge on this forum. You are a blessing. I think I have a loose connection somewhere as it’s intermittent. When I raise the boom up it hardly moves but if I blip some of the switches (like speed) it starts working for a few times. Same goes for forward and reverse. Any ideas would be greatly appreciated.
 

TJK

Member
Joined
Jul 23, 2022
Messages
9
Location
Indiana
I also have had a problem with the drive motors ever since I owned it. It will drive forward in high and low with ease but reverse always has less moving power and slower in low while high is pretty much useless bogging the engine down and barely moving at all.
 

OFF

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Sep 30, 2009
Messages
1,047
Location
Alberta, Canada
Occupation
HD Mechanic
Hi everyone just came across this forum while searching for manuals for my 40f. First I want to say thanks to everyone sharing their time and knowledge on this forum. You are a blessing. I think I have a loose connection somewhere as it’s intermittent. When I raise the boom up it hardly moves but if I blip some of the switches (like speed) it starts working for a few times. Same goes for forward and reverse. Any ideas would be greatly appreciated.

Welcome for the heavy Equipment Forum.
I would start with your machine by checking the voltage available in the basket. Any of the yellow wires in the basket control box will be the voltage supplied to all the controllers and toggles. You'll be lucky to have 12 volts way up there (long run of cable), but if it drops to less than 11 volts, things start acting up.
The foot switch is a trouble spot for voltage drops, but it could be any of toggles in there dragging it down.
If you'd like a 40F manual set, just send me a PM with your email and I'll send you the files right away.
 

OFF

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I also have had a problem with the drive motors ever since I owned it. It will drive forward in high and low with ease but reverse always has less moving power and slower in low while high is pretty much useless bogging the engine down and barely moving at all.

That one I would start by centering the drive valve on the proportional valve bank. I've detailed the procedure here in this thread a time or two.
 
Last edited:

OFF

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Centering
On the proportional valve bank, on the bottom side, you will find three 1/2" lock nuts around Allen head screws. The drive is the section with the biggest hoses.
Loosen the lock nut on the drive section
With the engine running on ground control, turn the screw in until the tone of the hydraulics changes, signaling the start of that function.
Turn the screw in the other direction until the tone of the hydraulics changes again, counting the number of turns of the screw from one to the other.
Turn the screw to the half way point between the two, and lock it down.
A good safety measure would be to jack the drive wheels off the ground during this btw. This would allow you to see the movement begin rather than sense it begin. Also keep you from getting run over should things go wrong. :) Centering lift & swing would not have the same potential for personal injury of course.
 

TJK

Member
Joined
Jul 23, 2022
Messages
9
Location
Indiana
Thanks OFF , I’ll see if I can figure out how to send you a pm . You nailed it, I checked and only have 10.2 volts on the yellow wires. I’ve been tracing wires all day and looks like the power is 10.2 coming from the back. The battery is coming in at 14.1 volts with engine running. I’ll keep tracing.
 
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