Front end loader control is stuck.

[PETDOC]

B2710 Kubota with 430 hours. Several months ago the control for lowering the front end loader became difficult to engage. Bucket tilt works fine. Problem progressed to where I had to raise the front end loader then snap the joy stick down to get it to move the rod into the control box. Last night it stuck in the down position. With the bucket on the ground I had to back the tractor to the barn. I removed the control box cover, loosened the 2 Allen bolts that hold the small ring around the rod, spayed with WD40, detached the joy stick and rotated the rod to and fro--all to no avail. The rod is still stuck in the down positioning in the control box.
Any suggestions would be appreciated.

 

[Tx Jim]

More than likely the problem is on the opposite end of the spool located with the detent spring. I presume the control is fine and not sticking.

 

[art]

chances are your detent has come apart and you will need to take apart the valve.

 

[PETDOC]

Jim,
I do all the of the maintenance and repairs to my motorcycle and much of it on my car, but hydraulics are a bit foreign to me. Can you elaborate on the spool and detent spring? When you ask if the control is fine the bucket tilt function works fine, but the control for the lift part is buried in the small cigar-shaped box and the joystick is immovable in a forward or backward position.

 

[PETDOC]

chances are your detent has come apart and you will need to take apart the valve.

Is the detent inside the metal box of the control unit? Do you or anyone else have a link to a schematic showing the parts of the control box?

 

[Leejohn]

Here is the loader for my B7800, now you can see where the parts are. This might not be ths same as yours, but should help some.

 

[J_J]

I would suggest removing the spool and check for debris, rubber, metal, etc.

Just remove the valve lever or cable.

Remove the end cap. Remove the float assemble and spring centering assembly, and then remove the spool and check inside the spool housing and spool for damage. With all the parts off of the spool, it should just slide freely in the spool bore.

The detent is inside the end cap.

Things could have come loose, and if so, and you know where all the parts go, then reassembly and check for free movement.

 

[PETDOC]

Thanks for all the helpful advice. LeeJohn thanks especially for the schematic on your loader, an LA402. My loader is an LA401 so I suspect the differences are minimal. I removed the entire hydraulic control unit and was sorely tempted to remove the end cap; however, never having before worked on hydraulic systems I decided to take it to a neighbor who repairs tractors for a living. As soon as I get the answer I'll post the result.
Curious if anyone has ever replaced the Husco control valve with one made by Prince? It would be nice to have something where the OEM would sell parts directly to the public.

 

[J_J]

Loader valves are fairly standard.

IN port
OUT port
PB port
4 work ports

A good valve will have regen and float and PB.

Here is a joystick loader valve you might use as a replacement.

Surplus Center - 2 SPOOL COMPACT 10 GPM JOYSTICK CONTROL VALVE

No regen on this valve.

Surplus Center - 2 SPOOL 14 GPM PRINCE LVR JOYSTICK LOADER VALVE

You should have seven hoses connected if using PB port.

 

[PETDOC]

J.J.,
Thanks for the information. My loader control does have a joystick and 7 hoses attached. I went to the Husco web site and believe the hydraulic control used by Kubota on my loader is the Husco 9210. Please excuse my ignorance, but what do the terms regen and PB stand for?

 

[Leejohn]

I would keep the valve you have, it's a good working valve. My brother has the prince valve and doesn't work near as good as mine.

 

[J_J]

Regen is a function that allows for fast cylinder extend or fast dumping for the bucket. It takes the rod side fluid and adds it to the pump flow into the base end, increasing GPM, and therefore more speed.

PB = power beyond , which is used to pass pump fluid to the next valve safely. The PB port with adapter can handle the pressure developed by the cyl or whatever is using the fluid.

 

[PETDOC]

And the rest of the story..... I removed the Husco hydraulic control box and took it to a local guy who works on tractors. He removed the lower end cap on the spool that controls the boom function. The detent spring and ball bearing in the end had rusted. He explained the symptoms were related to the end ball bearing not moving out of the way to allow the other 4 ball bearings to properly seat in the end of the spool when I pushed the joy stick forward. That would explain the initial difficulty in getting the boom spool to go down and the eventual locking of the spool in the down position. He soaked the rusted parts and removed the rust. After I re- installed the unit it works like new. One question still remaining- is this likely to happen on the bucket spool as well?

 

[J_J]

The float spool has a detent with balls and groove, whereas the tilt has none.

However, they both have spring centering springs, and if not stainless, they can perhaps rust and get crud inside and jam up thing.

You might use a waterproof grease and make sure the water hole is at the bottom of the spool for proper draining.

If the valve is at a bad angle for draining, you might drill a new hole.

 

[J_J]

These are Prince loader valves. Your Husco valve might be similar.

Look at this PDF pages 10 to 14, and you will see what is under those caps, and how everything goes together.

http://www.princehyd.com/Portals/0/valves/LvManual.pdf

 

[jodebg]

The float spool has a detent with balls and groove, whereas the tilt has none.

However, they both have spring centering springs, and if not stainless, they can perhaps rust and get crud inside and jam up thing.

You might use a waterproof grease and make sure the water hole is at the bottom of the spool for proper draining.

If the valve is at a bad angle for draining, you might drill a new hole.

JJ-My LA402 valve is frozen. Think I need to drill a hole to try to drain when it thaws. Can I drill the hole without taking anything apart-control valve fully assembled and on the tractor?

Where do I drill the hole..in the side of the lower caps, or in the round piece at the bottom of the lower caps?

 

[wdchyd]

Not a good idea to drill anything out without removing cap from valve....you run the risk of doing more damage and you need to clean up the parts anyways

 

[J_J]

The cans may already have a weep hole, but you have to remove the cans to check.

If there is no weep hole, drill a small hole at the lowest part of the can so any moisture can flow out.

When and if you lube, do not stop up the hole.

 

[jodebg]

When I remove the cans, do other internal parts come out/fall out, and is it difficult to reassemble?
Wondering what to expect before I disassemble?

 

[wdchyd]

If the valve is a standard spring-centered....NO

if the valve has float or any type of detent...YES

not difficult to disassemble if the screws are not corroded badly ......and sometimes you need to remove the valve assy from the tractor.....do not remove the spool unless you are gonna reseal the spool