damage from stopped flow?

[emanaresi]

My Kubota l4610 with bradco backhoe has been at my brothers house for a couple weeks because we trenched in some new lines to his garage. Today he decided to do some grading and took off the backhoe attachment. He didnt know that you have to change the hose for the pto at the front end loader valve when you remove the backhoe. I believe I have heard that if you stop flow in open center hydraulics it can cause major problems. Is this true? How quickly will the problems emerge and what parts of the system will be damaged? I am more than a little irritated and worried that he could have damaged my tractor. But he's my brother, what can you do....

Please help me to understand what kind of damage may have occurred and how to check for it.

 

[J_J]

The relief valve on the FEL or BH would have gone into relief, and it would screech until the pressure was relieved by connecting the hose to complete the flow path.

As far as damage, you may have caused some damage such as the pump, hose, fittings, cracked valve, etc.

If you have no visible leaks, and the hyd seem to be working fine, then you may have no damage.

You could use a hyd gage and check the relief pressure.

 

[dfkrug]

You did not say how much grading your bro got done.

If your hoe is powered thru the power beyond output from your FEL valve, then all
your implement pump flow went thru your system relief valve. That won't hurt
anything if you don't run it too long.

You WILL experience the noise of the RV passing full flow, and the tractor's hydraulics
will be sluggish and weak. If running this way for more than a minute or two, your
hyd fluid will get really HOT. Your engine will also labor to run the hydraulic pump
and the drive wheels when you try to drive. If you are used to operating the tractor,
you will notice something is wrong.

 

[emanaresi]

Ok, I think everything is ok then. Unfortunately, I can't go check it now but he didn't run it long. I will get him to check it over good and make sure there aren't any hydraulic leaks.

 

[emanaresi]

Believe me, I am not happy, but I think its ok. Like said abovem there is a relief valve, so hopefully all is ok. The backhoe was attached to the power beyond port on the loader valve and you are supposed to swap it for the pto line when you remove the backhoe. I did tell him this when I told him about how the backhoe CAN be removed. I did not think he would remove it. I think things are ok, but yes, he will not be playing with it unsupervised anymore.

 

[emanaresi]

Woohoo!! he dodged a bullet this time. Turns out he connected the in and out lines for the backhoe together so the fluid was getting to the tank.

 

[TomSeller]

I have a similar setup and yes, you are correct, the backhoe runs off the power beyond and needs to be manually switched between the 3 point and the backhoe. But the FEL relief as everyone is saying would protect the flow. There should not have been any deadheading. He should have caught a clue the way it would be acting and with the noise of the relief.

 

[emanaresi]

Yeah, but since he hooked the backhoe in and out hoses together, the fluid just went from the power beyond port right to the tank, so it didn't even need to bypass. Like I said, he got lucky.

 

[J_J]

How did he use the grader blade with out the 3pt?

 

[emanaresi]

He was just back dragging with the bucket. Not really grading I guess.