Backhoe Slow Dipper Stick Cylinder

[JeffandTamara]

I have a Great Bend 851 Backhoe that has developed a Slow reaction on the dipper Stick. Appears it happens on the Extend of the Dipper Stick only and happens about the same place with about 5" of stroke remaining. Going up seems to be fine. All other functions operate properly. Anybody have an idea for what might be going on?

Thanks for any ideas....

 

[Wayne County Hose]

Is it starting to leak at all? It sounds like a bent rod, a dented tube, or something loose inside. My guess would be a bent rod but it's just a guess.

 

[kennyd]

Could be a bent rod as Andy suggested, or it could be something other than the cylinder, like the boom is tweaked?

 

[JeffandTamara]

Thanks for the Reply's

No Leaks I can detect...I will try to remember to put some cardboard under it to make sure.

I don't know of anything that I have done to the Backhoe that would have bent something. But...I did notice a couple of "pops" when extending the dipper Stick. They were strange but I hadn't used it for a while so, I did'r really pay much attention to them. This seemed to happen about the time the response problems started showing up. About the most I have used the thing this year is to grease it up.

 

[john_bud]

Can you inspect it to see if there is a rock or stick in a bind when it extends?

I don't know if you can do it, but can you pull the cylinder pin and see if the stick moves freely without hydraulics?

Then with cylinder still disconnected, see if the cylinder moves freely without the stick attached.

There's not terribly much that can get goofy on you. Cylinder leak, cylinder damage, stick binding, stick hitting something, control leaking.

jb

 

[Airic]

This is probably not it but, have you checked your lever that lifts and lowers your 3-point to be sure it is in neutral? I had a similar problem with my backhoe and scrached my head raw trying to figure out what was going on till I found that the lever was slightly out of neutral. This lever is tied to the same hydralic lines and if you bump that lever out of possition just a little when using the backhoe it can exhibit the issues you describe.

 

[Wayne County Hose]

Thanks for the Reply's

No Leaks I can detect...I will try to remember to put some cardboard under it to make sure.

But...I did notice a couple of "pops" when extending the dipper Stick. (

Oh if it's a bent rod, you won't need cardboard. Just look at where the rod exits the gland.

A couple pops? Makes me think bent rod even more. Do yourself a huge favor. Do not use the backhoe until you determine the problem. If it is an internal cylinder problem, you can probably salvage most of the cylinder. I have a cylinder here in my shop from an old ford backhoe that the idiot operator kept using after he had this same issue. It took me about 3 hours to disassemble the cylinder and after I got it apart, the only thing good on the cylinder was the fittings that were screwed in to the ports.
You can see where the rod was rubbing the cylinder housing. I could have saved the piston and housing if he stopped using it.

Now I don't know if yours is a cylinder problem or not. What I'm saying is don't let a minor problem become a major problem.

 

[JeffandTamara]

First off THANKS AGAIN for all the responses....

JB.... I think you are right...to see what is really going on will take some time to take things apart and see if there is something binding. Right now, I am gonna say there hasn't been any more of the "pops" and the cylinder and dipper seem to operate smoothly. (Except for the few inches of stroke where it seems like the hydraulics have to catch up to the position of the dipper
Can you inspect it to see if there is a rock or stick in a bind when it extends?

I don't know if you can do it, but can you pull the cylinder pin and see if the stick moves freely without hydraulics?

Then with cylinder still disconnected, see if the cylinder moves freely without the stick attached.

There's not terribly much that can get goofy on you. Cylinder leak, cylinder damage, stick binding, stick hitting something, control leaking.

jb
__________________

Airic ....I forgot to say that this is PTO pump unit..so the 3-Pt hitch position should not be a factor.
Airic

This is probably not it but, have you checked your lever that lifts and lowers your 3-point to be sure it is in neutral? I had a similar problem with my backhoe and scrached my head raw trying to figure out what was going on till I found that the lever was slightly out of neutral. This lever is tied to the same hydralic lines and if you bump that lever out of possition just a little when using the backhoe it can exhibit the issues you describe.



Wayne County.... So far no leakage... and I can't see any scoring on the cylinder... Is there a way to check for a Bent Rod other than a leak?

I was wondering about a control valve problem. Perhaps valve is not opening up correctly and when the Dipper is coming down it might be leaking somehow and getting ahead of the hydraulic fluid flow... then when the fluid catches up it goes back to operating under power??? I don't know enough about hydraulics to understand why or why not that might happen...Maybe a hydraulics wizard could comment on the theory....



Oh if it's a bent rod, you won't need cardboard. Just look at where the rod exits the gland.

A couple pops? Makes me think bent rod even more. Do yourself a huge favor. Do not use the backhoe until you determine the problem. If it is an internal cylinder problem, you can probably salvage most of the cylinder. I have a cylinder here in my shop from an old ford backhoe that the idiot operator kept using after he had this same issue. It took me about 3 hours to disassemble the cylinder and after I got it apart, the only thing good on the cylinder was the fittings that were screwed in to the ports.
You can see where the rod was rubbing the cylinder housing. I could have saved the piston and housing if he stopped using it.

 

[amitysanimal]

Try and grab the stick boom and see if you can move it back and forth, make the piston go in or out. Just thinking maybe the nut on the inside that holds the gland has come loose.

amitysanimal

 

[JeffandTamara]

Looking at this some more, I can say when I raise the dipper stick it goes up smooth and fast, appears to operate properly. When I bring it back down, it seems to go a little too fast, almost like it is freefalling. When it gets to a certain point it comes to a stop and within a second or just a little more, it seems like the Hydraulics catch up and begin to apply pressure to move the dipper stick all the way in ( dipper stick cylinder completely extended).

Can anyone seen this before and help explain this phenomena?