Loader slow until using 3 pt lift

[kuducastle]

Older L3600 with Bush Hog 2346QT loader, runs great but recently the loader operates very slowly unless I lift the 3 pt hitch or use very high throttle. Loader has often been used at its limit lifting heavy logs. I suspect some sort of stuck relief valve??. Both lifting cylinders have been replaced, no hydraulic leaks. With 3 pt lifting, loader seems to have normal lift capacity. Where do I start?

 

[Fedup]

What valve operates the loader? Is a part of the Bush Hog package? Does it have six lines on it or seven? Is it directly connected into tractor hydraulics or supplied from another valve?

That might offer a starting point.

 

[TheOldHokie]

Older L3600 with Bush Hog 2346QT loader, runs great but recently the loader operates very slowly unless I lift the 3 pt hitch or use very high throttle. Loader has often been used at its limit lifting heavy logs. I suspect some sort of stuck relief valve??. Both lifting cylinders have been replaced, no hydraulic leaks. With 3 pt lifting, loader seems to have normal lift capacity. Where do I start?

Is the loader slow, weak, or both?
Does the bucket curl and dump normally?
Is this a Bush Hog loader valve or Kubota valve?

 

[kuducastle]

What valve operates the loader? Is a part of the Bush Hog package? Does it have six lines on it or seven? Is it directly connected into tractor hydraulics or supplied from another valve?

That might offer a starting point.

Bush hog valve controller, 6 lines, connected directly to engine.

 

[kuducastle]

Is the loader slow, weak, or both?
Does the bucket curl and dump normally?
Is this a Bush Hog loader valve or Kubota valve?

By itself, very slow and yes weak. When I pull up on the 3 pt, normal speed and strength. Bucket curls and dumps same speed as loader arms.

 

[TheOldHokie]

By itself, very slow and yes weak. When I pull up on the 3 pt, normal speed and strength. Bucket curls and dumps same speed as loader arms.

Something is blocking the down stream circuit.

Need more detail on this story.

Has the loader been working OK prior to this?
Where is the 3pt lever when its slow?
Does loader speed slow down when 3pt lift gets to top?
Is bucket slow when lift is slow?

Dan

 

[TheOldHokie]

Is the loader connected to this block on the side of the tractor? If so is the control screw I have circled in red turned straight up?

Dan

 

[North Idaho Wolfman]

Does the loader keep working when the three point lever is up position or does it only work when your moving the lever?

 

[kuducastle]

Something is blocking the down stream circuit.

Need more detail on the 3pt part of this story.

Where is the 3pt lever when its slow?
Does loader speed slow down when 3pt lift gets to top?
Is bucket slow when lift is slow?

3pt level all the way down when slow, loader seems to work best as 3 pt is lifting, slows down again when 3 pt gets to top. Yes, bucket is slow when loader is slow.

Does the loader keep working when the three point lever is up position or does it only work when your moving the lever?

I usually have to work the 3 pt lever for lift. When the 3 pt stops, the loader slows.
BUT - Dan nailed it! That screw was 30 degrees off. Turned it straight up and down and loader working fine. Thanks so much for all the help.
Ed

 

[TheOldHokie]

I usually have to work the 3 pt lever for lift. When the 3 pt stops, the loader slows.
BUT - Dan nailed it! That screw was 30 degrees off. Turned it straight up and down and loader working fine. Thanks so much for all the help.
Ed

Great!!! With the screw out of position you weren't getting full pressure out. Raising the 3pt back pressured the circuit and bumped loader pressure up. When 3pt stopped no more back pressure. I will have to add this one to the "known oddities" file.

Dan

 

[TheOldHokie]

I’d check the loader quick couplers and valve linkage before suspecting the relief valve.

1. Disconnect and reconnect each loader coupler. Check for a collar that is not fully latched or a damaged tip. A partially connected coupler can restrict flow.
2. With the tractor off, move the joystick and watch the control-valve linkage and spools. They should return fully to neutral and reach full travel in both directions. Fix any binding first.
3. If those checks pass, have pressure and flow tested at the correct ports while operating the loader and 3-point. If the loader speeds up only when the hitch is moved, that points to a hydraulic supply or valve problem rather than the new lift cylinders.
4. Do not open hydraulic lines or adjust relief settings without the proper gauges, fittings, and procedure. High-pressure oil can penetrate skin.

I found https://heavyequipmentfix.com/ useful for comparing equipment symptoms and repair information. You can put the machine details in its AI answer tool for a more specific check.

You really should read thes threads and consider the symptoms befote posting.

Ask your AI engine and see if it figures this one out. Remember to tell it the loader worked fine when the 3pt cylinder was extending but not when the cylinder was not moving.

We already know the answer from post #10 - deduced by understanding the circuit and putting two and two together

"With the (outlet block selector) screw out of position you weren't getting full pressure out. Raising the 3pt back pressured the circuit and bumped loader pressure up. When 3pt stopped no more back pressure. "

Dan