The JLG 40F Boom Lift Dilemma

[RSIGuy]

Willie, was it you that had hydraulic filters available if so would like to purchase one?

 

[Grovecomm]

I'm new here and not having any luck searching for other threads on a JLG 40F. Does anyone know of others?

 

[RSIGuy]

OFF, looking for a filter are any available, thanks.

Well......you'll need to support the boom on something very solid while you work. Higher the better. The best way is an overhead crane if your shop has one, if not a vehicle hoist, a large mound of earth, or even the roof of a sturdy building. Be carefull, don't take any risks. You're directly in the line of fire if that boom should fall for any reason. I would try and leave the barrell of the cylinder in place, just undo the gland and remove the piston & rod, reseal it, checking the bore of course while it's opened up. If it's scored, you'll have to pull the barrell also.

Hydraulic filter is JLG #2120055. I've never been able to cross that to anything.
(if you're not in a big hurry for it, I can send you one )

 

[OFF]

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.

Welcome RSIGuy

Between the frame rails on the drive end of the machine you'll see a removable cover. Under it is a valve block called a "transmission valve" that controls
the flow of drive oil. Sounds like maybe one of the spools is stuck. Try swapping hoses from side to side on the block output side and see if your drive wheel changes.

 

[OFF]

OFF, looking for a filter are any available, thanks.

I have one #2120055 filter left. Have you priced one out from your local dealer or rental company? Might be cheaper than the postage to send you one from here.

Edit: I just pulled out the new filter and a tape measure, did some searches. Try either a Baldwin PT579 or a Wix 51436. Measurements are almost dead on and they look very similar in the picture. I'm pretty sure they are the same filter. Check it out.

 

[OFF]

I'm new here and not having any luck searching for other threads on a JLG 40F. Does anyone know of others?

This is the main 40F thread. There may be a few other smaller ones dealing with specific problems or something like a Wisconsin engine thread but most of it is contained in here. What'cha lookin for?

 

[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?

 

[OFF]

View attachment 101224

Best way to tell what that is - pull the wires off it and see what stops working

(pretty sure that's high drive alright)

 

[RSIGuy]

Best way to tell what that is - pull the wires off it and see what stops working

(pretty sure that's high drive alright)

Thanks a bunch! As you may have guessed we're unsure because of the fact one drive unit isn't spinning. I attempted to try the swap you suggested but ran out of time. Two more questions if I could, is the other side of that the high speed valve low speed and since I'm a novice on hydraulics is the spool fixable (providing I knew what it was) should that be the problem?

 

[Grovecomm]

I'm just ALWAYS looking for more information. I've only scanned through these 746 posts and am amazed at the content, it's already answered a lot of my questions. It's great. BTW, I just struck a deal for $2K on my 40F. Now if the snow ever melts in northern WI I can hopefully tow it to my property up there. I see you're a bit farther north than I am...

 

[OFF]

Thanks a bunch! As you may have guessed we're unsure because of the fact one drive unit isn't spinning. I attempted to try the swap you suggested but ran out of time. Two more questions if I could, is the other side of that the high speed valve low speed and since I'm a novice on hydraulics is the spool fixable (providing I knew what it was) should that be the problem?

There is only one drive valve. It's in the group of 3 valves mounted low in the chassis. (lift/swing/drive) Hi drive will be a single solenoid valve that opens & adds extra hydraulic flow/increased volume to the drive circuit.

As far as that transmission valve goes, you should be able to save it just by taking it apart and cleaning it up, looking for broken springs, making sure the spools operate smoothly in the bores, etc. Rust is enemy.

 

[RSIGuy]

Hello Gurus of the 40F! I can't seem to get a good answer on the hydraulic fluid around here. The manual calls for Sun 2105 and no one can find it or a crossover. I've looked into a bunch and the viscosity index (170) is throwing me for a loop.
What should I put in there?
BTW OFF, thanks again for the last reply's and was able to cross those numbers to a Napa1436 so will take the old one over there shortly to make sure.

 

[OFF]

Hello Gurus of the 40F! I can't seem to get a good answer on the hydraulic fluid around here. The manual calls for Sun 2105 and no one can find it or a crossover. I've looked into a bunch and the viscosity index (170) is throwing me for a loop.
What should I put in there?
BTW OFF, thanks again for the last reply's and was able to cross those numbers to a Napa1436 so will take the old one over there shortly to make sure.

What we always used in them was a common #22 hydraulic fluid. That was the standard. In colder weather however that didn't work very well (-20 to -40 range).
We've also used ATF, synthetic ATF, and 0W30 motor oil.

 

[RSIGuy]

Hydraulic Fluid

What we always used in them was a common #22 hydraulic fluid. That was the standard. In colder weather however that didn't work very well (-20 to -40 range).
We've also used ATF, synthetic ATF, and 0W30 motor oil.

Thanks again! What a difference talking with someone who knows these things.

 

[RSIGuy]

I'm out working on the lift and electrician Bud has a question: per the manual schematic it shows a select relay and a high drive relay we never ran across either one, are they not on all models?
One other question is the high drive solenoid mounted on the rail with the rest, we wouldn't be asking stupid questions but as with most posts I've read the wiring has been #%****%^***, the only original was going up the boom?

 

[RSIGuy]

There is only one drive valve. It's in the group of 3 valves mounted low in the chassis. (lift/swing/drive) Hi drive will be a single solenoid valve that opens & adds extra hydraulic flow/increased volume to the drive circuit.

As far as that transmission valve goes, you should be able to save it just by taking it apart and cleaning it up, looking for broken springs, making sure the spools operate smoothly in the bores, etc. Rust is enemy.

I had a thought is it possible there is nothing wrong with my drive motor because we only tested it in auxiliary power mode, should I wait until Saturday when I run the motor to bring full pressure before I swap motors and tear into transmission valve? Just thinking.

 

[OFF]

I had a thought is it possible there is nothing wrong with my drive motor because we only tested it in auxiliary power mode, should I wait until Saturday when I run the motor to bring full pressure before I swap motors and tear into transmission valve? Just thinking.

Yes, wait and see. You may only have had enough volume to drive one wheel and not enough to center the spool.

 

[OFF]

I'm out working on the lift and electrician Bud has a question: per the manual schematic it shows a select relay and a high drive relay we never ran across either one, are they not on all models?
One other question is the high drive solenoid mounted on the rail with the rest, we wouldn't be asking stupid questions but as with most posts I've read the wiring has been #%****%^***, the only original was going up the boom?

crawl under the engine and look up. Mounted to the cross member behind the engine and maybe on the sides on the frame you will see solenoid style relays. 2 of them are for dump valves, one for the horn, and if there are 4, one will be for the
high drive. All those solenoids are together, yes. In the main control box there is a Potter/broomfield relay but it's function is high idle. If there is a select relay it will also be in the main control box.

 

[Grovecomm]

OFF, you are amazing on these machines! How did you learn these things so well?

 

[OFF]

OFF, you are amazing on these machines! How did you learn these things so well?

Well.....I was a young mechanic, they were new, everybody was scared to work on them. I'm a firm believer in "if you don't know how it works, you don't have a hope of fixing it" so I jumped in with both feet and learned. The company I worked for owned four or five 40F's, a 50F, about four 60F's, and an 80F that all required a lot of TLC. I understood them, I loved them, and I kinda miss them. Crazy huh?
My glory days.