LA 302 loader issue

[DC64]

Hi all,

My LA 302 loader boom will not lower without using the float function. it will only lower without using the detent when I am curling the bucket up or down. As soon as the bucket is curled completely the boom will stop.
same thing raising the boom under load. It will only go up while actively curling up or down.
any thoughts to steer me in the right direction?

 

[DC64]

It boggles my mind because I thought both circuits were separate loops

 

[woodman55]

Have you replaced or uncoupled any hoses recently ?

 

[DC64]

Have you replaced or uncoupled any hoses recently ?

Yes, because of a burst line I replaced two. But the issue was happening before. I actually bought the thing with the issue.

 

[PoTreeBoy]

Yes, because of a burst line I replaced two. But the issue was happening before. I actually bought the thing with the issue.

There appears to be two ( at least) versions of this loader. On one the valve stays on the tractor when the loader is removed. On the other, the valve stays on the loader. I think you may have a couple of hoses crossed.

Can you post a picture of the valve and clearly note where each of the seven hoses go? Maybe post another picture of the hydraulic block and note where the hoses from the valve go?

 

[RCW]

We’re the broken hoses to the loader from the valve, or from the tractor to valve?

Something is not right. I would recheck hose routing and also make sure all couplers are properly seated. Easy things that don’t cost anything.

 

[DC64]

Here are they

 

[DC64]

Here are they

Valve location

 

[TheOldHokie]

It boggles my mind because I thought both circuits were separate loops

Normally the bucket and boom spools are connected in parallel so there is interaction.

On some Kubota loader valves float dumps the lift cylinders to tank via the T port on the valve but power down dumps the cylinders via the power beyond port. If a down stream valve is not in neutral it can block the power beyond flow and prevent the loader from lowering.

Dan

 

[DC64]

Normally the bucket and boom spools are connected in parallel so there is interaction.

On some Kubota loader valves float dumps the lift cylinders to tank via the T port on the valve but power down dumps the cylinders via the power beyond port. If a down stream valve is not in neutral it can block the power beyond flow and prevent the loader from lowering.

Dan

Right, I just figured that out looking at the schematics. Very confusing to follow. It looks like the hoses are right because with help from another input it ends up working in the direction it’s supposed to.
So I have to open it up and check if I can find anything inside the valve body? What if the relief valve is set to low?

 

[PoTreeBoy]

Right, I just figured that out looking at the schematics. Very confusing to follow. It looks like the hoses are right because with help from another input it ends up working in the direction it’s supposed to.
So I have to open it up and check if I can find anything inside the valve body? What if the relief valve is set to low?

Yes, it is plumbed correctly. And all 3 versions have a series valve on the boom.

Confirm that your 3PH is not all the way up and relieving.

 

[PoTreeBoy]

Right, I just figured that out looking at the schematics. Very confusing to follow. It looks like the hoses are right because with help from another input it ends up working in the direction it’s supposed to.
So I have to open it up and check if I can find anything inside the valve body? What if the relief valve is set to low?

I wouldn't tear into the valve just yet.

Does the bucket curl and dump normally when you control it without moving the boom?

Does the 3PH work normally?

It seems to me to be acting as if the PB circuit is blocked downstream of the valve.

 

[TheOldHokie]

Yes, it is plumbed correctly. And all 3 versions have a series valve on the boom.

Confirm that your 3PH is not all the way up and relieving.

Good advice - no need to disassemble the valve at this point. Focus your diagnostics at the external connections on the valve.

The relief valve has nothing to do with the problem.

A tee and pressure gauge on the PB outlet would be informative.

Are there any additional valves such as rear remotes or third function downstream of the loader?

Dan

 

[PoTreeBoy]

Good advice - no need to disassemble the valve at this point. Focus your diagnostics at the external connections on the valve.

The relief valve has nothing to do with the problem.

A tee and pressure gauge on the PB outlet would be informative.

Are there any additional valves such as rear remotes or third function downstream of the loader?

Dan

OP, building on what TheOldHokie asked, I see you have a backhoe in your equipment list. Is it mounted/installed?

Follow the hose you marked 'from 2' and tell us where it goes.

You've brought up the relief valve a couple of times. Do you hear fluid flow when the tractor is running but nothing is being moved?

 

[TheOldHokie]

OP, building on what TheOldHokie asked, I see you have a backhoe in your equipment list. Is it mounted/installed?

Follow the hose you marked 'from 2' and tell us where it goes.

You've brought up the relief valve a couple of times. Do you hear fluid flow when the tractor is running but nothing is being moved?

A $15 pressure gauge and $5 tee installed at the power beyond outlet on the loader valve will diagnose functioning of that circuit. Its also a valuable addition to any tractor owners tool chest.

My bet is the circuit is blocked for reasons unknown and the pump is dead headed against the loader relief. But I have been wrong before.

Dan

 

[DC64]

Yes, it is plumbed correctly. And all 3 versions have a series valve on the boom.

Confirm that your 3PH is not all the way up and relieving.

It’s in the up setting.
guy I got it from saidhe always left it there.
But didn’t know much about it either

 

[DC64]

I wouldn't tear into the valve just yet.

Does the bucket curl and dump normally when you control it without moving the boom?

Does the 3PH work normally?

It seems to me to be acting as if the PB circuit is blocked downstream of the valve.

Yes the bucket works normally
the 3PH is just powering the hoe, and it works.
the issue occurs both with the PTO not engaged and engaged

 

[DC64]

Good advice - no need to disassemble the valve at this point. Focus your diagnostics at the external connections on the valve.

The relief valve has nothing to do with the problem.

A tee and pressure gauge on the PB outlet would be informative.

Are there any additional valves such as rear remotes or third function downstream of the loader?

Dan

I ordered a gaug, couple days and I should have it
no rear remotes just the hoe

 

[TheOldHokie]

It’s in the up setting.
guy I got it from saidhe always left it there.
But didn’t know much about it either

Lower it and leave it there!!! If the 3ot is locked down by the hoe the 3pt will deadhead the pump and you will have exactly the priblem you are describing.

Where does the hoe get hydraulic power?

Dan

 

[DC64]

OP, building on what TheOldHokie asked, I see you have a backhoe in your equipment list. Is it mounted/installed?

Follow the hose you marked 'from 2' and tell us where it goes.

You've brought up the relief valve a couple of times. Do you hear fluid flow when the tractor is running but nothing is being moved?

the hoe is mounted and working

“from 2“ goes to “to 2” in the other picture. The upper one on the tractor

I don’t really different noise when nothing is moved or when the boom or bucket get to end of it’s travel.