Hydraulic Problem - Bucket Won't Uncurl

jcorsico · Sep 7, 2016

Hi -

I have a compact utility tractor with a front end loader and pallet forks. While using the tractor the other day, I accidentally dug the edge of the bucket into the ground while driving forward at speed. The hit was pretty hard, and my chest slammed into the steering wheel.

After that impact, the bucket no longer un-curls. It curls fine. It goes up and down fine, but if you try to uncurl, it moves about 1 inch and then stops.

I tried reversing the hydraulic lines (curl hydraulic circuit to lift cylinders, and vice versa), and the curl feature then works fine. So there is nothing wrong with the curl cylinders.

Any ideas what this could be?

The other odd behavior is that the curl circuit will not depressurize. In other words, even if I turn the tractor off, lower the bucket to the ground, and then move the joystick around, the curl circuit remains fully pressurized. The other circuits de-pressurize, like you would expect. This is probably why it won't uncurl? If the curl circuit is always pressurized, then the uncurl circuit is going to be fighting the curl circuit.

What would cause the curl circuit to not depressurize?

Thanks!
Jon

DDoug · Sep 7, 2016

jcorsico said:
What would cause the curl circuit to not depressurize?

Thanks!
Jon

A Hydraulic quick coupler unseated (slightly)

jcorsico · Sep 7, 2016

digger doug said:
A Hydraulic quick coupler unseated (slightly)

Already tried repeatedly connecting and disconnecting the quick couplers...

motion guru · Sep 7, 2016

Given that you have swapped lines and the cylinder works in the opposite direction as desired, it is likely that the circuit has a piloted check valve in it. I have a woods loader on my Kubota - it will hold a 2000 lb load on the forks with extremely fine control. This is because it has a piloted check valve in the lift and curl circuits. If you damaged the piloted check valves, that would explain why the rod side of the cylinder will not depressurize.

Mud · Sep 7, 2016

Maybe damage to the spool valve? Did you have your hand on the lever when you hit the wheel?

DDoug · Sep 7, 2016

jcorsico said:
Already tried repeatedly connecting and disconnecting the quick couplers...

And why didn't you state this in you original post ?

I've frankly had enough of the post's like yours, as Forrest called the "Ya butts"

We offer suggestions, you trickle more and more snippets of info, with "Ya butt I already
tried this"

jcorsico · Sep 7, 2016

Mud said:
Maybe damage to the spool valve? Did you have your hand on the lever when you hit the wheel?

I will be honest with you - I have no idea. It all happened very fast.

jcorsico · Sep 7, 2016

motion guru said:
Given that you have swapped lines and the cylinder works in the opposite direction as desired, it is likely that the circuit has a piloted check valve in it. I have a woods loader on my Kubota - it will hold a 2000 lb load on the forks with extremely fine control. This is because it has a piloted check valve in the lift and curl circuits. If you damaged the piloted check valves, that would explain why the rod side of the cylinder will not depressurize.

I have no idea if it has a piloted check valve. I will check. Thank you!

jcorsico · Sep 7, 2016

digger doug said:
And why didn't you state this in you original post ?

I've frankly had enough of the post's like yours, as Forrest called the "Ya butts"

We offer suggestions, you trickle more and more snippets of info, with "Ya butt I already
tried this"

Maybe if you actually read the original post, you would have seen that I already swapped the hydraulic lines around.

DDoug · Sep 7, 2016

jcorsico said:
Maybe if you actually read the original post, you would have seen that I already swapped the hydraulic lines around.

Your now playing lawyer here.

I specifically said if a Quick coupler is not fully engaged (still locked on) it will dead end.

I'm done with you and your multiple problems, not the least is your hydraulic problem.

true temper · Sep 7, 2016

There should be a plug on the top and bottom in line next to the bucket spool on the control valve. Remove them and I bet you will find your problem. They are circuit relief or load check valves as Motion stated.

ewlsey · Sep 7, 2016

digger doug said:
We offer suggestions, you trickle more and more snippets of info, with "Ya butt I already
tried this"

Why would he post a question here if it was some no brainer issue like a quick coupler?

Posting on an internet forum is the last act of desperation, not the place you start.

jcorsico · Sep 7, 2016

true temper said:
There should be a plug on the top and bottom in line next to the bucket spool on the control valve. Remove them and I bet you will find your problem. They are circuit relief or load check valves as Motion stated.

Here is a part drawing of the valve. Are you referring to items 16, 17 and 18?

Thank you!

ces224 · Sep 7, 2016

Have you tried removing the couplers from the hoses and switching them. It sounds like your quick coupler ball is stuck and not letting flow threw.

Sent from my iPhone using Tapatalk

true temper · Sep 7, 2016

jcorsico said:
Here is a part drawing of the valve. Are you referring to items 16, 17 and 18?

Thank you!

View attachment 179940 View attachment 179941

What kind of tractor loader do you have? That control valve is a bit different than most. Yes I am thinking #16 might be stuck, that's a pretty simple valve.
Does the valve spool work free? Also double check your quick couplers on the tractor side, something might be stuck.

true temper · Sep 7, 2016

When you switched hoses around and the bucket started working, did you try to see if the boom would raise and lower?

HuFlungDung · Sep 7, 2016

Check for bent rods on those cylinders. I've seen guys make bananas out of their bucket cylinders by driving over the bucket while 'grading'. Slightly bent rods may still retract if there is enough force available. Extend the cylinder rods fully and put a straight edge on them.

jcorsico · Sep 8, 2016

These are all good ideas. I will try them when I can get back to the tractor. It's a John Deere compact utility tractor, 2032R.

Thanks again!
Jon

jcorsico · Sep 9, 2016

Problem solved! It was a broken quick coupler. :angry:

I cannot tell how the coupler failed. It looks perfectly normal, and works in your hand perfectly fine. Low pressure fluid (such as water coming out of a faucet) flows through the coupler normally. But high pressure fluid somehow causes it to shut.

I changed the coupler after running out of other ideas. I replaced both the male and female ends. Doing this was a guess, as I didn't think the coupler was broken..

Thank you all for your help!

Jon

ewlsey · Sep 9, 2016

ewlsey said:
Why would he post a question here if it was some no brainer issue like a quick coupler?

Fuck

Hydraulic Problem - Bucket Won't Uncurl

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