Couple farm questions, backhoe and post driver

[MtnViewRanch]

Originally Posted by bindian

Either by settling down on the stabilizers and bucket or upon blocks OR temperature changes.........all you have to do is wiggle (bled down) the BH controls before hooking up.
hugs, Brandi

Brandi, if the hydraulics are hotter than when the hoe was removed, won't there be pressure built up on both sides? Yes you can equalize the pressure, but won't there still be more pressure on the system than when the hoe was removed, thus putting excess pressure on the QDs?

I don't have a removable hoe, so I am not familiar with what works with them and what doesn't, I just know what happens with my grapple and how I have to deal with it.

[Redneck in training]

I am not hydraulic expert but it seems to me because of cylinders have unequal volume on each side. If the cylinder is extended (by wiggling valves) it will return less oil than it takes in therefore even small extension might relieve the pressure in the system. If force (in example weight of the machine) causes the cylinder to retract the pressure might increase. Is my thinking correct?

[bindian]

Originally Posted by MtnViewRanch

Brandi, if the hydraulics are hotter than when the hoe was removed, won't there be pressure built up on both sides? Yes you can equalize the pressure, but won't there still be more pressure on the system than when the hoe was removed, thus putting excess pressure on the QDs?

I don't have a removable hoe, so I am not familiar with what works with them and what doesn't, I just know what happens with my grapple and how I have to deal with it.

Brian,
Usually the hydraulics are warm (especially if using tractor hydraulics) when you remove a BH. The warmth is from running the tractor as you unhook and "walk" the BH off of the subframe. Once you move a control valve on a disconnected BH, the pressure goes to zero. I wiggle the remotes and the BH controls before and after disconnecting and connecting and I haven't had a problem. I wiggle the BH controls after I sit her down on huge blocks (12 inch square and high). But you got me thinking. My 511 BH ops manual shows a placard (decal) that says..........Petcock..open to relieve pressure before connecting fittings. I would have to look on my BH to find it, as the placard is on the control valve cover. I guess the petcock is between the control valve and the quick disconnect.
hugs, Brandi

[MtnViewRanch]

Originally Posted by bindian

Brian,
Usually the hydraulics are warm (especially if using tractor hydraulics) when you remove a BH. The warmth is from running the tractor as you unhook and "walk" the BH off of the subframe. Once you move a control valve on a disconnected BH, the pressure goes to zero. I wiggle the remotes and the BH controls before and after disconnecting and connecting and I haven't had a problem. I wiggle the BH controls after I sit her down on huge blocks (12 inch square and high). But you got me thinking. My 511 BH ops manual shows a placard (decal) that says..........Petcock..open to relieve pressure before connecting fittings. I would have to look on my BH to find it, as the placard is on the control valve cover. I guess the petcock is between the control valve and the quick disconnect.
hugs, Brandi

Brandi, I understand that if the tractor has been used that the fluid is warm if not hot. But lets say that you take the hoe off first thing in the morning, tractor is air temp, say 65 degrees. You use a 3pt implement until mid afternoon. Now the air temp is 95 degrees. All the fluid has warmed up 30 degrees, if not more from the hoe setting in the sun, anyway, it has expanded for sure. Now at this time is there trouble hooking up the QDs? Find that petcock and everybody's problems will be solved.

[bindian]

Originally Posted by MtnViewRanch

Brandi, I understand that if the tractor has been used that the fluid is warm if not hot. But lets say that you take the hoe off first thing in the morning, tractor is air temp, say 65 degrees. You use a 3pt implement until mid afternoon. Now the air temp is 95 degrees. All the fluid has warmed up 30 degrees, if not more from the hoe setting in the sun, anyway, it has expanded for sure. Now at this time is there trouble hooking up the QDs? Find that petcock and everybody's problems will be solved.

You will still have less pressure on one side or the other of the valve or actuator in the system. Say you don't bled down pressure from the BH when you disconnect. The BH settles down and the temp heats up. Since there was less pressure on one side, it will be the same ratio of pressure when it settles and the sun get hot. So moving a control back and forth will cure that problem. It is the line from the valve to the quick disconnect that would be what the petcock is for. The only way other way is to crack a line or like you said.............install a bleeder and a T to bled it. But that adds a lot of extra cost and a mess when cracking a line at a QD will do the same thing for free. My QDs are a 90 degree type to clear my seat. I am not sure if there is enough room to add a T and bleeder there
hugs, Brandi