Bent rods in FEL bucket cylinders

[pmmully]

Well, my education into the FEL 1150SG loader bucket curl malfunction on the used L48 continues.... the used dealer called today and said both rods in the bucket cylinders are bent. I expected the relief value to not let that happen? Well, I guess that assumes there is a relief valve in that circuit. The causes I have read about so far are improper installation alignment and excessive side loads, or an impact at speed. All make sense. It is possible tooling around with the bucket hanging down like a limp you know what could have done it?

Anyway, it's on the way to being fixed with new rods, at my expense. They tell me it did not leave that way. I know I never lifted a thing... will check on the dude I left it with, but he owns his own L31 so I would be surprised if he really did do something not kosher, but maybe. It ain't worth arguing about.

I know of my ASV skid steer, you could hardly hurt the thing it was so strong. But then again, it was a steer, everything was a lot shorter and stouter.

 

[i7win7]

It is possible tooling around with the bucket hanging down like a limp you know what could have done it?

YES if you had ground strike

 

[Kennyd4110]

When the valve/joystick is centered (as in neutral), there is no relief valve in the circuit-that's on the pump side of the valve.

 

[lugbolt]

seen it a few times. Almost every time, it was due to back dragging with the bucket curled all the way or close to all the way forward. When the operator has the weight of the tractor on the forward-curled bucket, going backwards, the cylinder is fully extended. Then they hit something. Rock, driveway crack, whatever. This places a huge load on those cylinders and can bend the ram rod(s). It may not be a lot of bend but it doesn't take much to cause issues. Don't backdrag with the bucket curled all the way forward.

Backhoes have a safety valve built into the valve assembly which helps helps reduce shock load. Loaders dont' have a safety valve. They have a relief valve which allows hydraulic fluid to be returned should the pump's pressure exceed the valve's rating. It does not protect the system from improper use. So why didn't they put safety valves on the loader? Cost. Generally speaking it is not a needed feature on a loader with additional costs involved if it was added would put the cost of the new tractor beyond competitor's equipment unless they reeduced cost elsewhere which means removing a component or feature. Manufacturing and marketing is a pain in the butt.

 

[AC 715b]

So why didn't they put safety valves on the loader?

Because it would be inconvenient if the loader were to dump it's load unexpectedly after lifting a load. And could also be expensive, depending on the cargo.

 

[Magicman]

Been there, done that, and it's an expensive mistake.

 

[pmmully]

Been there, done that, and it's an expensive mistake.

You really can not put any valves on the system to prevent this from happening in my case. It is not a hydraulic pressure issue. It is a physics issue. The bucket was fully, or nearly fully extended, when a large object was pushed. The rods bent near the piston ends. It is pretty easy to see what happened.

A ground strike in this position can do it also as pointed out. Maybe there was a ground strike, maybe the bucket rolled up on the object, or maybe it was just too heavy. Regardless, it was an operator error. I would have maybe made the same mistake. I saw this operator do the same thing on his own Kubota, bit that is a much smaller machine, with much shorter tubes, and he was/is lucky. The two bent tubes are now trophies on the wall.

 

[Magicman]

I completely agree. Abnormal leverage against a component will cause abnormal issues. Luckily I only bent one rod.