JLG 80F hydraulics getting real hot, real fast

[falcondan]

Hi everyone......very new to this group. Just looking at some of the forum and this looks like a great resource.

This is third party problem. A friend has a JLG 80F that he recently purchased that worked "OK" at first. The hydraulic pump failed so he had it rebuilt by the closest dealer. Reinstalled with new filters......5 days later, the pump failed again. Dealer didn't want to deal with it so he took it to a reputable hydraulic company. Rebuilt again, new filters....now it works OK, but the hydraulics heat up real quick and quit working. I'm a heavy equipment mechanic, but have limited electronic and boom lift experience. I'm hoping there is a somewhat simple solution for him. (Doesn't everyone!!)

Thanks in advance for any light you can shed!!
Dan

 

[OFF]

Welcome falcondan! You found both the "stacked" hydraulic filters in side the tank, right? And the high pressure filter mounted by the valve body? The 80F's always ran hot.....the hydraulic tank too hot to touch. Has anyone checked the system pressures?

 

[falcondan]

Hello OFF and thanks for the reply! He did find and replace the stack filters (return?) each time the pump was repaired. I don't believe he is aware of the high pressure filter. I downloaded some manuals for an 80H, but don't know how similar it is to the 80F. His biggest problem is location...he is dismantling an old wooden grain elevator in a small town as far away from services as you can get. The nearest JLG service location wants $600 just for the round trip, and like all of us he would like to get the simple stuff out of the way first. I'll let him know about the high pressure filter and hopefully he has a way to check pressures. Again, thank you!!!
Dan

 

[falcondan]

Forgot to ask.... I assume by the description that the high pressure filter is not a screw on filter, right? And it is located near the valve body? Thanks
Dan

 

[OFF]

Forgot to ask.... I assume by the description that the high pressure filter is not a screw on filter, right? And it is located near the valve body? Thanks
Dan

It's an aluminium can about 3" in diameter that screws off and exposes a cartridge type filter inside. It filters everything that enters the main proportional valve bank. In really old machines, this filter was inside a cast iron housing and much larger.
Does this machine have outriggers?

 

[falcondan]

No outriggers, The tires/axles extend out for added stability. I'll call him and have him look for the filter/canister. He did not mention another filter, so I am assuming he isn't aware of it.
Thanks!!
Dan

 

[falcondan]

On update......I talked with the owner just now and have determined that he has a myriad of problems that are going to need professional attention. The hydraulics don't change speed with the engine at idle or at rated rpm. It locked up on him this morning and all controls wanted to extend the boom....he ended up climbing down the side of the elevator to get down. I have not seen the lift, but he is convinced there is no other filter than the two in the tank. He is going to "baby" it until he is done with this project and then seek help. Maybe the best direction.

Thanks for the input, OFF!!!!

Dan

 

[barklee]

On update......I talked with the owner just now and have determined that he has a myriad of problems that are going to need professional attention. The hydraulics don't change speed with the engine at idle or at rated rpm. It locked up on him this morning and all controls wanted to extend the boom....he ended up climbing down the side of the elevator to get down. I have not seen the lift, but he is convinced there is no other filter than the two in the tank. He is going to "baby" it until he is done with this project and then seek help. Maybe the best direction.

Thanks for the input, OFF!!!!

Dan

If you are having unintended controller functions or a general failure, i WOULD NOT suggest running that machine until it can be properly repaired!!! Im not trying to be the guys nanny, i just dont want to see anyone get hurt! This is a good post and i would like to see what you come up with.
Thanks

 

[falcondan]

Hi Barklee and thanks for the reply! If I had a day or two to describe this fellow, it might not be enough time. Don't get me wrong.....he is a good fellow, just lives on the edge. There are not helpers or employees running this lift just him, and I suspect that it would take more than an 80 foot drop to concrete to hurt this guy!! Anyway, he has the highest work done and won't be more thank 20-30 fee off the ground to finish. He wants done before the cold sets in too much. (He is in Lakeview, OR) He reassured me it will head for a shop as soon as it's feasible and I will keep you posted what he learns.

On a side note he did say that all the functions were real slow until the first pump rebuild. They operated just like they should for 4 or 5 days and then got extremely slow. That is when he shipped the pump out a second time. When it was installed the functions were still slow and he found foaming in the tank. I had him check and he found a gasket on the suction side leaking. Gasket fixed and it worked like it should for another 3 or 4 days. Now it runs slow until the oil gets hot and then just quits. I'm wondering if the pump cavitated enough to damage it. When it messed up and trapped him, he happen to be right by a steel exterior ladder on the elevator so luck was with him.

Thanks again

Dan