Post Hole Digger (PHD) Hydraulic Down Pressure (HDP) Kit Installation

[MtnViewRanch]

UPDATE: I installed the down pressure kit. It installed reasonably easy other than I had to go to the hydraulic store to get several fittings to complete the installation. It doesn't work properly. The hydraulic extends fine but does not contract. I have trouble shot it and determined that the only way to relieve the pressure in order to contract the cylinder is to remove the pressure reducer. It doesn't make sense. Any thoughts on what I might be doing wrong?

Assuming that you now have everything plumbed per the directions?:confused3: The cylinder will not retract on it's own. It should collapse when the PHD is raised. The 3pt has more strength than what the pressure bypass has and allows the cylinder to retract. The cylinder only adds pressure. Because of the pressure bypass valve, it is not locked solid like a std cylinder would be when the control valve is in neutral.

If you remove the pressure bypass, you will have other problems to contend with. DO NOT remove the bypass valve.

 

[JD 4520]

Assuming that you now have everything plumbed per the directions?:confused3: The cylinder will not retract on it's own. It should collapse when the PHD is raised. The 3pt has more strength than what the pressure bypass has and allows the cylinder to retract. The cylinder only adds pressure. Because of the pressure bypass valve, it is not locked solid like a std cylinder would be when the control valve is in neutral. If you remove the pressure bypass, you will have other problems to contend with. DO NOT remove the bypass valve.

Yes, I do have everything plumbed per the directions whereby the pressure is running off of my 3rd SCV. I have not been able to get the cylinder to collapse on its own. I have had to lessen a fitting to relieve pressure in order to get it to collapse. It seems to me that the pressure bypass is not properly working or it would allow for the pressure to do as you state and the cylinder to retract. Could anything else be wrong in this situation?

 

[J_J]

Is that cyl an SA cyl with one hose or a DA cyl with two ports and two hoses?

An SA cyl needs weight to retract, either pushing or pulling..

Show pic of your down pressure kit.

What pressure bypass are you talking about?

If your DA valve controls the cyl, one direction of the lever will extend the cyl, and the other direction will release the fluid and cause the valve to go into relief. One work port should be plugged, or a hose from that work port should go to tank.

 

[MtnViewRanch]

Yes, I do have everything plumbed per the directions whereby the pressure is running off of my 3rd SCV. I have not been able to get the cylinder to collapse on its own. I have had to lessen a fitting to relieve pressure in order to get it to collapse. It seems to me that the pressure bypass is not properly working or it would allow for the pressure to do as you state and the cylinder to retract. Could anything else be wrong in this situation?

So have you tried to raise the PHD and it will not raise? I guess that I don't understand how it is that you know that the relief is not working? You are not going to collapse the cylinder by hand. Sorry for the questions, just trying to understand what all you have done. :confused3:

 

[JD 4520]

Is that cyl an SA cyl with one hose or a DA cyl with two ports and two hoses? An SA cyl needs weight to retract, either pushing or pulling.. Show pic of your down pressure kit. What pressure bypass are you talking about? If your DA valve controls the cyl, one direction of the lever will extend the cyl, and the other direction will release the fluid and cause the valve to go into relief. One work port should be plugged, or a hose from that work port should go to tank.

I will get pictures later today as that may help. It is a single.

 

[JD 4520]

So have you tried to raise the PHD and it will not raise? I guess that I don't understand how it is that you know that the relief is not working? You are not going to collapse the cylinder by hand. Sorry for the questions, just trying to understand what all you have done. :confused3:

Yes I have tried and it will not collapse. I cannot collapse it by hand either. Only way to collapse it to remove the valve. I tried to collapse it by removing the lines to see if there was anything to do with the lines or connectors but still would not collapse. It is like it's holding the pressure.

 

[MtnViewRanch]

Yes I have tried and it will not collapse. I cannot collapse it by hand either. Only way to collapse it to remove the valve. I tried to collapse it by removing the lines to see if there was anything to do with the lines or connectors but still would not collapse. It is like it's holding the pressure.

You should not be able to collapse it by hand. Is the relief valve adjustable? If so, it is set too high.

 

[JD 4520]

Is that cyl an SA cyl with one hose or a DA cyl with two ports and two hoses? An SA cyl needs weight to retract, either pushing or pulling.. Show pic of your down pressure kit. What pressure bypass are you talking about? If your DA valve controls the cyl, one direction of the lever will extend the cyl, and the other direction will release the fluid and cause the valve to go into relief. One work port should be plugged, or a hose from that work port should go to tank.

Pictures do help. I removed the cylinder from the PHD since it easily detaches with a couple of pins. I will attempt to adjust the tension. Instructions tell you how but warn not to.

 

[J_J]

If the SA cyl provides down pressure, does the cyl not retract by raising the 3pt.

One of the other manufacturer suggested that you need a float valve to operate the unit.

 

[JD 4520]

If the SA cyl provides down pressure, does the cyl not retract by raising the 3pt. One of the other manufacturer suggested that you need a float valve to operate the unit.

The SA cylinder does not retract when raising the 3 PT. I may need to check into the float valve idea.