The JLG 40F Boom Lift Dilemma

[OFF]

Was that recommendation for the oil/diesel mix in the Bertea manual? We used to mix 50/50 Kerosene and ISO22 hydraulic oil (I couldn't think of ISO yesterday) in the winter, but that was before synthetic oils were invented. Never had a pump fail, but it was always a risk. Modern oils are much better.

The hydraulic filter was the same for all the F series JLG's. The 80F had two of them stacked. I had a couple left, but I think I finally threw them away somewhere at the start of 2025. That part number you posted doesn't sound right. I looked it up, the tank filter is a number 2120055

 

[OFF]

The high pressure filter canister weighs about as much as a large dog, and is very tight. Like a 48" pipe wrench with a 6ft snipe on the end kinda tight. No fun at all. But I believe Bertea systems also had smaller inline filters between the pump and the valve bank. Have a look.

 

[maple2]

Thank you Off and willie59 for the great information. I found the small high pressure filter, it is identical to the one pictured on page 21 of this thread. It's about the size of a coffee cup. Put a pipe wrench on it today that thing did not move a hair. I was hesitant to turn it more, did not want it to break. Is this filter under pressure maybe? Looks like maybe a bleeder screw on top of this filter. Maybe crack that a little let some pressure off? I looked everywhere for the high pressure canister filter that weighs as much as a large dog! Could not find anything like that. What area would that be located?

 

[willie59]

I'm going way out on a limb of memory here, but there's something telling me there's a fine mesh screen within the Bertea servo where the pilot oil enters the servo to prevent debris from getting in that area, have to take it apart to find it. But I could be wrong, been too many years. And years ago I've worked on old Skyworker bucket trucks from back in the 70's, the bucket control didn't use pilot pressure oil from the pump to operate, like most bucket truck controls do, nope, the controls on those things were their own independent hydraulic system. Had a small reservoir of oil at the bucket controls. Once you got all the lines bled of air, when you work the actuator at the bucket, each function acted like a master cylinder that would send oil down the boom lines to the valves at the lower. I recall on those machines you had to use ISO 22 cut 50/50 with Kerosene. If you didn't the oil was too thick to work the controls.

 

[OFF]

Thank you Off and willie59 for the great information. I found the small high pressure filter, it is identical to the one pictured on page 21 of this thread. It's about the size of a coffee cup. Put a pipe wrench on it today that thing did not move a hair. I was hesitant to turn it more, did not want it to break. Is this filter under pressure maybe? Looks like maybe a bleeder screw on top of this filter. Maybe crack that a little let some pressure off? I looked everywhere for the high pressure canister filter that weighs as much as a large dog! Could not find anything like that. What area would that be located?

That picture on page 21 of this thread, circled as #4, is a newer version of the old type high pressure filter I was thinking of. The old version is huge. In the 40F parts manual, page 2-57 figure 5 shows the big old beast.

Page #2-65, figure 2-36, item 67 is the inline filter used in the Bertea systems.

 

[wiseman9986]

I just joined the club I purchased a 75? 40fn last night. Im not sure what is all wrong with it yet I need to get an alternator belt and it is leaking inside of the boom. What hydraulic fluid should i run? Im pretty sure if have the bertea valves.

 

[wiseman9986]

Ill try to post some pictures once i have enough posts I looked through most of this thread yesterday and I didn't see any 40fn im guessing the n is narrow

 

[wiseman9986]

Here's a couple

 

[wiseman9986]

 

[OFF]

Welcome! Yes, N is for narrow and you have Bertea valves and controllers. And I see it's been converted to propane. Everything working or unknown at this point?

 

[wiseman9986]

Welcome! Yes, N is for narrow and you have Bertea valves and controllers. And I see it's been converted to propane. Everything working or unknown at this point?

What i was told was that everything was working then about a year or so ago when they tried to move it only forward or reverse worked. Well I loaded it and looked at it in the middle of a rainstorm. They installed a new battery it starts and runs but the alternator belt was missing and kept losing voltage so nothing was working great. But once it was drove and winched up the trailer it did drive both directions. But fluid coming out of the boom had to hold the boom in with a come-along. Hopefully i can get a belt for the alternator and find the leak next week
Hopefully its just a hose i will probably be replacing all of them anyway but if its a cylinder i can handle that also.

 

[wiseman9986]

Ok i got it looked at a little bit functions are strange it always wants to boom up but the up and down controls mostly dont work from the basket. I can control up and down from the back but its still always trying to go up i had to hold down most of the time. Telescope works but pours fluid out of the boom when i retract looks like that cylinder is going to be the first project. All of the toggle switches are kinda touchy i think I will just replace them all. Steering does not move at all i can hear something happen but they dont try to move ive tried with the black knob in and out. Im sure i need hydraulic fluid haven't decided what to use