Boom on Woods BH9000 backhoe leaksdown? (2024)

I have a Woods BH9000 backhoe on my L3710. The dipper leaks down pretty quick when I move the tractor. What’s the best way to tell if the valve or the cylinder itself is the cause?

Bob

unioncreek said:

I have a Woods BH9000 backhoe on my L3710. The dipper leaks down pretty quick when I move the tractor. What’s the best way to tell if the valve or the cylinder itself is the cause?

Bob

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If the cylinder is retracting it can only be the valve.

If its extending you can.test the cylinder by disconnecting the base end hose and plugging the port on the cylinder. Operate valve to retract cylinder and if there os an internal leak it will extend instead.

Dan

TheOldHokie said:

If the cylinder is retracting it can only be the valve.

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This is something I've wondered about ... is it possible for a the piston seal to be leaking enough to allow (in this case) the dipper stick to sag, but not leaking so much that the pump can overcome the leakage to pressurize and retract the cylinder? Or is it pretty much an all-or-nothing deal?

TheOldHokie said:

If its extending you can.test the cylinder by disconnecting the base end hose and plugging the port on the cylinder. Operate valve to retract cylinder and if there is an internal leak it will extend instead.

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Why do you say "if it's extending"? Wouldn't the test still work? Or is the point that if it's leaking down in extension, but also not extending under pressure, then it's clearly an internal leak and not the valve so there's no point in testing?

ejb11235 said:

Why do you say "if it's extending"? Wouldn't the test still work? Or is the point that if it's leaking down in extension, but also not extending under pressure, then it's clearly an internal leak and not the valve so there's no point in testing?

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I was simply differentiating cases.

If its collapsing under load it has to be from an external leak not internal piston seals. You know that without any additional testing.

There could still be an internal leak causing other problems like loss of extension force or drift in the extend direction. In that case you need to test the cylinder to differentiate internal versus external.

And of course it could be both internal and external.

Dan

ejb11235 said:

This is something I've wondered about ... is it possible for a the piston seal to be leaking enough to allow (in this case) the dipper stick to sag, but not leaking so much that the pump can overcome the leakage to pressurize and retract the cylinder? Or is it pretty much an all-or-nothing deal?

Click to expand...

If there is sufficient flow and the leak is relatively small the pump can overwhelm the leak but the cylinder wont hold under static load.

Dan

unioncreek said:

Dan,
Thanks for the info. Yes the cylinder is retracting. I’m not that knowledgeable about hydraulic and figured i had better ask.
Bob

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I.think you misunderstood what was asking. See my responses to ejb11235.

Dan