Branson bucket leaks down

[Shaunrtidwell]

I have been chasing a problem on my 4220i with the BL20 loader not holding pressure and leaking down.

I started having this issue after I replaced the quick connectors for the hoses at the control lever. It’s been about 6 months since I’ve done this so I’m ruling out air in the lines as it should have worked its way out by now.

I had no issues before replacing the quick connectors. Is there another check valve in the system that I’m not aware of?

Any ideas would be appreciated… Thank you

 

[oldnslo]

Is this the lift - lower cylinders that are drifting down? If yes and there are no external leaks allowing oil to drip on the ground you could have a direction control valve problem or piston seal leak on one or both of the lift cylinders.

If you have a way to support and lift the loader like a jack or chain hoist you can perform a simple test to identify which it item is leaking.

Raise the loader with the hydraulic on the tractor.
Support the loader and shut the tractor off.
Determine which hose is connected to the blind or piston end of lift cylinders and unplug that quick disconnect and only that one.

Now remove the support from loader and watch to see if it drifts down.

If yes one or both of the lift cylinders piston seal is leaking.

If no something in the directional control valve has changed allowing a little more leakage. This could be something preventing the centering spring from returning the spool to “home” position.

Note: you will need to lift and support the loader slightly to reconnect the quick disconnect.


If this is the curl - dump drifting I would suspect bad piston seals on tilt cylinders if there is no external leaks dripping on the ground

 

[ning]

I have been chasing a problem on my 4220i with the BL20 loader not holding pressure and leaking down.

I started having this issue after I replaced the quick connectors for the hoses at the control lever. It’s been about 6 months since I’ve done this so I’m ruling out air in the lines as it should have worked its way out by now.

I had no issues before replacing the quick connectors. Is there another check valve in the system that I’m not aware of?

Any ideas would be appreciated… Thank you

I assume you're talking "I can watch it leak down" vs "the bucket goes down overnight"?

 

[Stimw]

I had a problem with my 3510 bucket acting like it had air in the cylinders.
I found that a hose from the reservoir to the hydraulic pump had a split in it and it was sucking air.
Just a guess. ??

 

[Shaunrtidwell]

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I assume you're talking "I can watch it leak down" vs "the bucket goes down overnight"?

Yes it won’t hold up its own weight… curl is worse than lift.

As soon as I lift it and release the lever it starts to drop.

 

[Shaunrtidwell]

Is this the lift - lower cylinders that are drifting down? If yes and there are no external leaks allowing oil to drip on the ground you could have a direction control valve problem or piston seal leak on one or both of the lift cylinders.

If you have a way to support and lift the loader like a jack or chain hoist you can perform a simple test to identify which it item is leaking.

Raise the loader with the hydraulic on the tractor.
Support the loader and shut the tractor off.
Determine which hose is connected to the blind or piston end of lift cylinders and unplug that quick disconnect and only that one.

Now remove the support from loader and watch to see if it drifts down.

If yes one or both of the lift cylinders piston seal is leaking.

If no something in the directional control valve has changed allowing a little more leakage. This could be something preventing the centering spring from returning the spool to “home” position.

Note: you will need to lift and support the loader slightly to reconnect the quick disconnect.


If this is the curl - dump drifting I would suspect bad piston seals on tilt cylinders if there is no external leaks dripping on the ground

I’ve been thinking about this and it makes sense, but I don’t understand why changing the quick connects would have started the inter-cylinder leaks

 

[oldnslo]

I’ve been thinking about this and it makes sense, but I don’t understand why changing the quick connects would have started the inter-cylinder leaks

Changing quick disconnect should not have any effect on cylinder drift unless there is now an external leak at one of the disconnects.

 

[Zork]

My Tech found this today on my Ansung BL-20 loader bucket circuit.

Long story short- Curl cylinders were isolated to determine source of drift. Initial test months ago Indicated cylinders were fine. Curl circuit was now drifting due to left cylinder internal seal damage.