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.