B2601 FEL Bleed down

[msmcknight]

Hi everyone,

I have noticed in my B2601 with the LA434 that the loader doesn't hold it's pressure very well. I might not be describing this the right way... I'm a new owner, so please bear with me.

If the tractor is running and I have the loader w/forks set level at about 1.5 feet above the ground and I am running the tractor doing other PTO-driven tasks, I notice that the forks slowly find their way back to the ground.

I would expect this kind of leak-down when the tractor is turned off, say.. sitting over night or something, but to have it drop while the system is actively producing pressure seems odd.

Being new to tractors and hydraulics in general, this is a little concerning, but for all I know, it's normal. If anyone can clear this up for me, it would be appreciated.

Thank you,
-Michael

 

[Kennyd4110]

Re: B2601 FEL Pressure Drain

The term is called “leak down” most of the time, and a small amount is normal even when the tractor is running. If the valve is in neutral or centered, then the system has no way to hold or add to the pressure to the cylinders to maintain the level. I’d bet that Kubota has a published spec for allowable leak down, I know JD does, it’s measured in inches per hour. If you machine is under warranty, let your dealer know your concerns and get it documented.

 

[ItBmine]

Re: B2601 FEL Pressure Drain

I would have them do something about that. I had this tank and some oil (385 pounds plus the weight of the hardwood pallet) on mine all afternoon yesterday and it did not move at all.

 

[Dave_eng]

Re: B2601 FEL Pressure Drain

Hi everyone,

I have noticed in my B2601 with the LA434 that the loader doesn't hold it's pressure very well. I might not be describing this the right way... I'm a new owner, so please bear with me.

If the tractor is running and I have the loader w/forks set level at about 1.5 feet above the ground and I am running the tractor doing other PTO-driven tasks, I notice that the forks slowly find their way back to the ground.

I would expect this kind of leak-down when the tractor is turned off, say.. sitting over night or something, but to have it drop while the system is actively producing pressure seems odd.

Being new to tractors and hydraulics in general, this is a little concerning, but for all I know, it's normal. If anyone can clear this up for me, it would be appreciated.

Thank you,
-Michael

A little history and photo of your tractor would be enlightening.

By seeing your FEL valve, it informs those who don't know your model of loader what type of FEL valve and control lever on it. Larger tractors have cable operated joystick valves, some have a joystick mounted to the valve and some FEL valves have two levers

Model year, hours, how long have you had it, any sign of external hydraulic leaks. Is the issue with the loader arms, the bucket or both?

If just the loader arms, as a temporary test, swap the work hoses between the loader arms and the bucket to see if there is a change.

Dave

 

[msmcknight]

Re: B2601 FEL Pressure Drain

As far as I know, the LA434 has a single lever attached directly to the valve. The tractor and FEL are new -- bought it in december and it only has 22 hours on it. There have been no signs of any hydraulic fluid leaks anywhere.

Maybe someone here more familiar with the LA434 can tell you more about the valve. This is my first tractor so I'm certain there are others here that know a lot more about it than I do.

If I had to guess, I would say the leak-down is in the loader arms vs. the bucket pistons. When it sits for a period of time, the forks/bucket appear to lower in their last position. Meaning, it doesn't appear that the system as drooped into a "dump" position, but rather the main loader arms have simply rested back down to the ground.

If there is a leak-down issue, where does the fluid go? I don't see any evidence of it leaking outside of the system. Does it just eventually squirt back through the valve into the reservoir?

Thank you,
-Michael

 

[North Idaho Wolfman]

It's called bleed down, and it's the cylinder bypassing fluid from one side to the other through the internal seals.
It can also bleed down through a bad valve (rare) and FYI it wouldn't matter if it's a single handle (joy stick) or a dual handle, they both use the same spool valves, 2 of them.
Since it's under warranty have the dealer look at it and evaluate it.

 

[msmcknight]

Would that cause both cylinders to drop at the same rate? And, does that indicate failures in both main cylinders?

Seems like if it was only one cylinder failing, the FEL would drop at an angle instead of a practically level descent.

 

[Kennyd4110]

Would that cause both cylinders to drop at the same rate? And, does that indicate failures in both main cylinders?

Seems like if it was only one cylinder failing, the FEL would drop at an angle instead of a practically level descent.

The cylinders are plumbed in parallel, so if there is an issue with bypassing internally it can affect the other as well, meaning that the pressure can bleed off some and both cylinders can retract or extend depending on external forces.

Put the loader up and take a measurement, then let it sit for an hour and remeasure. If you feel the leakdown is excessive then call you dear as it's under warranty anyway. As I mentioned above they will have an allowable spec, so if it's under that than you will have to live with it like many other do. My first tractor had this issue since day one and in general use it never proved to be an issue, my current loader will stay up for days and not budge, just the luck of the draw.

 

[Tx Jim]

Would that cause both cylinders to drop at the same rate? And, does that indicate failures in both main cylinders?

Seems like if it was only one cylinder failing, the FEL would drop at an angle instead of a practically level descent.

Torque tube at the front of loader frame will make both sides of boom lower at same time not at an angle. Ditto what Kenny stated about boom cylinders having hoses connected together.

I think if boom is lowering excessively then spool valve is problem.

 

[lugbolt]

Raise loader about a foot off the ground. No load in the bucket or forks. Measure how many inches it's up of the ground.

Disconnect the quick couplers at the valve. All 4 of them.

Walk away from it.

After exactly 1 hour's time, if the bucket is within 2 inches of what it was before, you're in good shape.

If it's more than 2" lower, than one or both of the cylinders is leaking internally at an excessive rate; and you can let Kubota and the dealer work it out. If it didn't move at all, it's a valve problem-and kubota can deal with it. Loader has one year warranty on it. Tractor has two years. Pick up an delivery not covered.