New Holland L785 actuators

[brubro]

Hello all,

I've got a problem and thus a question about a New Holland L785. The main boom just started lifting slowly, and it is no longer lifting smooth. You can feel a jerkiness to it that was not there before. I am concerned that the actuators or the pump is in need of repair. There seems to be a new noise coming from the pump area. When I lifted the seat, I could see one of the actuators vibrating as the machine idled. The noise seemed to be in the general vicinity of that actuator.

The boom drops normally, as expected. The hydraulic fluid level is fine. The tilt works fine, so I am assuming that the pump is probably OK. I did a search on this forum and didn't really come up with anything similar. Can you rebuild the actuator (s) if they are the culprit?

Any advice, knowledge or experience would be greatly appreciated.

 

[brubro]

Anyone???

OK, maybe I don't want to accept the obvious, but let me know what you think.

 

[willie59]

Not familiar with your machine so I'm not much help. If your bucket tilt works properly, I don't think you have a problem with your pump. Not sure what your referring to as an actuator.

 

[brubro]

That is how I feel, that the pump is probably OK.

The actuator in question probably goes by a few names, as most things do. Here is a link to a site that shows diagrams:

http://www.messicks.com/nhparts/11262.aspx

After you go to the page, select "Boom & Bucket Cylinder Hydraulics" from the list on the left and an image of the hydraulics will show up. Number 1 is the actuator; there is one for each side of the main boom arm.

I have a bad feeling that the one is bad. I am most curious as to if it can be rebuilt as the price for a new one seems a bit steep. I am very good mechanically, but am not extremely knowledgeable about this particular part of the hydraulics, so I am looking for some information so that I can educate myself properly before completing the repair.

 

[2109 Stang]

brubro are you referring to the boom cylinder? the hydraulic cylinder that lift the boom? according to the pictures that's what I think you mean by actuator ,an actuator is basically the same but electric instead of hydraulic .

 

[brubro]

I'm referring to the item listed as #1 in the diagram, described in the literature as "actuator" under the item #1 description, on the right. That is what Messic's calls it, so that is what I am referring to it as.

The boom cylinder is not what I am talking about. That just takes a new seal kit if it is leaking.

All semantics aside, does anyone know if that is the likely issue for the problem that I described?

 

[willie59]

Item #1 looks like the bucket curl cylinders, not sure why they would use the term actuator (although that's what it is). These small cylinders are generally not that difficult to rebuild, but I don't know if that's what your problem is. I just don't know anything about this machine so I can't help you much. I hope you figure out what the problem is.

 

[2109 Stang]

Yes thats the bucket curl cylinder ,I don't think this is your problem, you might have a valve problem instead, the cylinder works when it gets oil pressure ,so you might be getting some oil restriction from the valve and that's why is making this noise ,I think.

 

[brubro]

Interesting...

The slow lift and the jerky motion is what is odd to me. I just don't have enough knowledge about the system yet to be able to pinpoint it. You can feel the vibration in the whole machine.

 

[2109 Stang]

brubro: place your question on the (General Industry question) section ,there is a lot more people reading than here and go to other sites ,I've got the feeling that your problem is a control valve.

 

[brubro]

Thanks, 2109 Stang. I'm still trying to get a handle on this forum and where to post things. I appreciate your help.

 

[old skool iron]

New Holland L785

Hello all,

I've got a problem and thus a question about a New Holland L785. The main boom just started lifting slowly, and it is no longer lifting smooth. You can feel a jerkiness to it that was not there before. I am concerned that the actuators or the pump is in need of repair. There seems to be a new noise coming from the pump area. When I lifted the seat, I could see one of the actuators vibrating as the machine idled. The noise seemed to be in the general vicinity of that actuator.

The boom drops normally, as expected. The hydraulic fluid level is fine. The tilt works fine, so I am assuming that the pump is probably OK. I did a search on this forum and didn't really come up with anything similar. Can you rebuild the actuator (s) if they are the culprit?

Any advice, knowledge or experience would be greatly appreciated.

brubro. I have the same machine. Had the same type of problem. It truned out to be the loader control valve.There was a small crack on the inside.It sits on the front lower inside of your cab by your feet. Good luck. OSI

 

[willie59]

I have the same machine. Had the same type of problem. It truned out to be the loader control valve.There was a small crack on the inside.It sits on the front lower inside of your cab by your feet. Good luck. OSI

old skool iron, believe it or not, this does happen. And it's one of the most impossible things to troubleshoot as there is no way to test it. I worked on a Case 1840 skid once with a Danfoss control valve, the arms and bucket were doing some weird things. You do first things first and re-seal the cylinders, then check any other components (like reliefs), and when satisfied all else is good...it's got to be a problem with the control valve. I put a new control valve on it...problem solved.

 

[old skool iron]

Loader control valve

old skool iron, believe it or not, this does happen. And it's one of the most impossible things to troubleshoot as there is no way to test it. I worked on a Case 1840 skid once with a Danfoss control valve, the arms and bucket were doing some weird things. You do first things first and re-seal the cylinders, then check any other components (like reliefs), and when satisfied all else is good...it's got to be a problem with the control valve. I put a new control valve on it...problem solved.

ATCOEQUIP. Yes sir good advice. I put new seals in my valve,when it blew them right away. l dug deeper and found a small hair line crack between the valves. Replaced the control valve.My skid works like new. Of course l hunted down a used one. Have you seen the price of a new one.By the way if brubro needs help finding one, get in touch. OSI

 

[brubro]

thanks!!!

Will check that out. I am doing a couple other things at the moment. I read elsewhere that air in the hydraulics might cause that so I am planning on bleeding the system first.

However, based on the last few posts, I will take a very close look at the control valves.