Backhoe boom drooping

[RPK]

I recently re-attached my Kubota BH-90 on my L3130. After about ten minutes of use I noticed the boom on the backhoe had dropped down considerably. I though I had hit the lever by mistake. That was not the case. I assume fluid is leaking by either at the piston or at the valve? I am not much of a mechanic but I could use some help trouble-shooting this. I have 225 hours on the tractor and it is a year and a half old. Thanks in advance for any help.

RPK

[rbargeron]

Could be air in the sytem - its good to cycle all the cylinders thru full travel after a re-attachment. If that's no help, with the bh bucket lifted a foot or so off the ground and all valves centered, and the machine shut off, disconnect the hydraulic couplers to the backhoe, blocking flow in or out of the control valve. If the boom continues to drop, it would indicate the leak-by is at the piston. If it drops a little but stops, that points to the valve.
Be careful since this would pressurize the exhaust hose - to reconnect the coupler, the pressure would need to be bled off by operating other valves to allow the boom to lower to the ground. Good luck. Dick B.

[mazurrj]

I guess you are saying it did not do this before. Because mine been that way since new. I keep the pin in unless I'm using it. Dealer said thats the way it is on this hoes. Others here with the BH-90 and 75 have said the same. Some leak down , some do not. Mine without pin can drop six inches in 20mins while riding along.

[RPK]

Thanks for the help guys. It hasn't done it before so maybe it is air in the lines. If that doesn't cure it, I had already planned on putting the transport pin in place. Thanks.

RPK

[hill]

I think it's pretty normal for any cylinder that's under a load of weight but not under pumped pressure to squeeze down some.

[crazyal]

It's probably your valve, I'm saying this because the seals in the cylinder are basically new. It's possible a very small metal shaving or something is keeping the valve from closing all the way. It could work it's way out or it could either damage the seat slightly or just stay there and you'll just have to live with it.

[eanjay]

Originally Posted by crazyal

It's probably your valve, I'm saying this because the seals in the cylinder are basically new. It's possible a very small metal shaving or something is keeping the valve from closing all the way. It could work it's way out or it could either damage the seat slightly or just stay there and you'll just have to live with it.

I would agree that it is probably the control valve. My dealer is replacing the control (under warranty). They can and did test the cylinders for leakage pretty easily, but in my case the 'sag in my FEL is also seen in the B'hoe and the 3pt hitch. This would seem to indicate a constant leak in the 'return' taking away from over-all hydraulic pressure - the system 'sags' even when under power. It would only need a 'leak' in one controller to affect a system with 'power beyond' feeding a B'hoe and a FEL etc. A cheaper fix would probably be to replace the valve seat.

Ean Jay