Hydraulic Cylinder Jerky

[confederatemule]

I had a cylinder on repaired on my ditch bank flail mower. In one direction it is very jerky. Is this air trapped in the system and will it work itself out?
The cylinder leaked when I extended it for the first time I tried to use it. Therefore I don't know if it jerked before I had it repaired. Due to circumstances beyond my control I did not put it on my tractor until the 2 year warranty had expired.
Thanks for any help.

Mule

 

[ptsg]

Does this cylinder have a pilot operated check valve? Similar to that valve block on top of the cylinder in the picture below:

Anyway, cycle a couple of times to rule any possible air in the cylinder, but I wouldn't push the lever all the way. I would just feather the controls to not let gravity take over and create a "sloppy bucket syndrome".

 

[MtnViewRanch]

99% of the time, you will solve your issue by installing a flow restrictor on both lines-ports.

 

[confederatemule]

Does this cylinder have a pilot operated check valve? Similar to that valve block on top of the cylinder in the picture below:

View attachment 5105656

Anyway, cycle a couple of times to rule any possible air in the cylinder, but I wouldn't push the lever all the way. I would just feather the controls to not let gravity take over and create a "sloppy bucket syndrome".

Here is a picture of it. I am assuming it must have a pilot operated check valve.

 

[confederatemule]

99% of the time, you will solve your issue by installing a flow restrictor on both lines-ports.

I may do that. Do you reckon it would help to install one on all four lines going to the mower? Should I install them at the control valve end or cylinder end?

 

[ptsg]

Here is a picture of it. I am assuming it must have a pilot operated check valve.

Yes. It does have the check valve and that's what I figured. Those valves tend to chatter when gravity takes over. Just like MtnViewRanch said, you'll need a flow restrictor.

 

[MtnViewRanch]

I may do that. Do you reckon it would help to install one on all four lines going to the mower? Should I install them at the control valve end or cylinder end?

If the cylinder pictured is the one with the issues, then the 2 supply lines to that cylinder.
I am not familiar with 4 lines to the mower.

 

[confederatemule]

If the cylinder pictured is the one with the issues, then the 2 supply lines to that cylinder.
I am not familiar with 4 lines to the mower.

Yes it is the cylinder in the picture. That cylinder tilts the mower. There is another cylinder that swings it out to the side and back. The side swing cylinder is very fast, so I will put a restrictor in those lines as well, I think.

 

[confederatemule]

The restrictors were delivered this evening. I will install them tomorrow, if the weather is not too bad. It is forecast to rain hard tomorrow. At this time I have to work outside. It is restricted down to 1/32.

Mule



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[confederatemule]

Now that a pilot operated check valve has been mentioned, what does it do?
Is it basically a one way valve?
The cylinder that swings the cutter assembly from side to side does not have a pilot operated check valve. In my mind it is not needed cause side to side is not as dangerous, nothing is going to fall. The cylinder with the pilot operated check valve could fall and possibly injure a person.

Mule

 

[oldnslo]

A pilot operated check is a load holding valve that prevent the cylinder from drifting under load. It requires a positive pilot pressure to open which typically comes from opposite end of the cylinder.

Does the swing cylinder allow the mower to move or swing away if it hits an object? If yes then you do not want a Pilot operated check in that circuit.

 

[confederatemule]

A pilot operated check is a load holding valve that prevent the cylinder from drifting under load. It requires a positive pilot pressure to open which typically comes from opposite end of the cylinder.

Does the swing cylinder allow the mower to move or swing away if it hits an object? If yes then you do not want a Pilot operated check in that circuit.

I have not actually used it in the field, yet. That may happen later today.

 

[confederatemule]

Update. I installed restrictors in each line. It made a BIG difference. The operation is very smooth and not too slow. Thanks for the help, Y'all.

Mule

 

[confederatemule]

Oldnslo, the side swing does not swing back if I bump a tree with the outer end of the cutter. I will have to sorta pay attention to what I am doing.

Mule

 

[oosik]

I experienced a similar situation with my first Tractor - Ford 1700. Back blade would shudder/jitter when being raised. I ran the blade thru multiple up/down full cycles - the problem went away. My conclusion - air entrapped in the hydraulic fluid.