Kubota SVL75-2 loader

[Walter63]

I have a question that someone my be able to help with. I'm using a 7 foot boom on my loader and I noticed that with an extra heavy weight, the loader can lift, but not curl. In fact, if the loader is curled and I make the lift, the loader will "uncurl" until it stops at its mechanical limit.
I can understand how the curl function might not be strong enough to work with a heavy load 7 foot out, but it seems odd that the load could "uncurl" under load. Shouldn't it at least hold in place?
The machine is in very good shape with about 800 hours on it. Hard to believe the curl cylinders would have internal leaks this early on.
Do I have a problem or is this normal ?

 

[ptsg]

It's probably normal. On industrial equipment, the control valves are usually fitted with safety relief valves for each work port. These relief valves are set at a much higher pressure than the system pressure.

If you put enough load on it, it will drift down on it's own.

Keep in mind that a load 7 foot away from the machine, will put a much higher pressure on the cylinders than a load closer to the machine.

 

[art]

You do have relief valves that are releasing as posted earlier. It is amazing with all the machines we sell some stop lifting but will still curl but then drop and some the tilt will break away first.

 

[Walter63]

You do have relief valves that are releasing as posted earlier. It is amazing with all the machines we sell some stop lifting but will still curl but then drop and some the tilt will break away first.

Thanks for both of your comments. In most of my other machines, tractors, etc., I can hear the relief valve when the loader is overloaded, so I'm familiar with that. I haven't, however, experienced a situation where a loader or a curl would actually drop when overloaded. That's the reason for my question.
The boom pole definitely puts extra load on both the lift and the curl. I was experimenting to see if I could still lift boulders with the boom out horizontal at 7'. At first, I thought it wouldn't, because the curl wasn't up to the task. But once the curl was at its mechanical limit (like it was fully dumping), the boom was at horizontal, and the lift worked fine. So for the task I had in mind, reaching way out to lift a boulder, it works OK after all.

 

[jk96]

I'm running an 84" inch brush cutter on a Case TR340. I think it weighs about 2300 lbs and it's size puts a lot of that weight way out in front of the pins. It will also slowly uncurl similar to what your seeing.

 

[Walter63]

I'm running an 84" inch brush cutter on a Case TR340. I think it weighs about 2300 lbs and it's size puts a lot of that weight way out in front of the pins. It will also slowly uncurl similar to what your seeing.

Thanks. Good to know that's normal.

 

[Rafter H]

I have a JD 326D which is about 70hp. I use a 12' boom to set trusses and lift AC that weigh 1,000 units on and off trailers. I also run a brush cutter that weighs 2600 lbs. It has 2200 hrs on it and doesn't uncurl. I also put a hay spike on my bucket and move, load and unload 1400 lb round bales. Will stay curl up as long as I want. This uncurling doesn't seem right to me.

 

[searcyfarms]

if its uncurling, its bypassing fluid in the cylinders usually indicating issues with seals, not always but 90% of the time that is it - i would agree that it could be a design thing but you would have to ask that question to kubota