Hydraulic question for post driver

[ch1ch2]

You could use a 3/4" ag coupler on that return line. It'd save threading and hose clamping when you attach and detach the post driver.

I like that idea.

 

[Birdhunter1]

You could use a 3/4" ag coupler on that return line. It'd save threading and hose clamping when you attach and detach the post driver.

I have thought about that, but what I built cost me nothing I hadn't already spent and the parts were on hand. Its not like it is a tool I hook up often and even when I do it isn't a big task to hook up. There are a few times a year when the driver will not work, when the ground is hard and dry it won't work well. On frozen ground it will if the freeze isn't deep, usually the top is frozen and down lower it is soft. Spring and the wet fall time is the best, even putting them in the ground in an area with a spring that I had to lay out a row of posts to drive the tractor on it still set posts solid.

 

[Zebrafive]

You could use a 3/4" ag coupler on that return line. It'd save threading and hose clamping when you attach and detach the post driver.

I question a 3/4" AG coupler would offer free enough flow.

 

[ch1ch2]

I question a 3/4" AG coupler would offer free enough flow.

You will always have the resistance that is in the return hose diameter. Usually a 1/2 in hose. I guess you could take off the coupler altogether and replace it with a union.

 

[almost canadian]

Thanks for all of the replies.

The post driver is on order and I may be back once it arrives and I can't work out how to connect it!

 

[ericm979]

According to Parker a 3/4" coupler is rated for 28 gpm (at what pressure they don't say, probably full pressure). That's the same as they say 3/4" hose is rated for.

 

[Birdhunter1]

I think some people just don't understand that this equipment has to have a free flow back to the sump and running through a coupler will restrict it. My machine has a 3/4" hose that pipes directly to where you pour hydraulic oil into the trans, that is what it has to have. There are only a few couplers that will work, they are quite expensive compared to just a few black iron pipe fittings at the hardware store. Before someone comments about black iron pipe not being able to withstand hydraulic pressures realize there is very little pressure on this line but alot of flow, in fact I think my return line from the driver is just a heater hose.

 

[almost canadian]

On a somewhat related issue, this is the first attachment that I have used that will require any form of hydraulics. I assume that, when I disconnect the driver, some of the hydraulic fluid will remain in the driver and its hoses. If I am correct, will I need to add some fluid to the tractor once I disconnect the driver? I will be keeping the driver in our Quonset when it is not being used. Although I live in Canada, our Quonset is heated so I am not too concerned about it freezing (if that is even possible) but, as it will now be exposed to air, will it deteriorate being in the hoses/driver? Should I attempt to get as much as the fluid back into the tractor?

 

[ericm979]

A coupler rated for the same flow as the hose is not going to be much of a restriction.

 

[ericm979]

On a somewhat related issue, this is the first attachment that I have used that will require any form of hydraulics. I assume that, when I disconnect the driver, some of the hydraulic fluid will remain in the driver and its hoses. If I am correct, will I need to add some fluid to the tractor once I disconnect the driver? I will be keeping the driver in our Quonset when it is not being used. Although I live in Canada, our Quonset is heated so I am not too concerned about it freezing (if that is even possible) but, as it will now be exposed to air, will it deteriorate being in the hoses/driver? Should I attempt to get as much as the fluid back into the tractor?

The couplers close off the flow when disconnected. So the oil will not flow out of the implement. AG couplers dribble about a half teaspoon of oil each time you disconnect them. A tiny amount of air may get into the coupler but you'll never notice it. Even if you did get significant air in there, the way to get it out is to operate the cylinder.

What will happen however is that if you disconnect it at temp X and then go to connect it when it's significantly warmer, the oil will have expanded slightly. That will make it difficult or impossible to get the connectors to seat (or to disconnect the connectors on the implement if theres one male and one female and you connected them together). If this happens you can loosen one of the connectors and let a little oil out (doesn't take much). But if you loosen an NPT threaded connection and re-tighten it, it will leak. Maybe not the first time but eventually. NPT seals by deforming the threads and that's not a reusable connection. I find it better to do my plumbing using JIC connectors and use adaptors to get to NPT for fittings that need it (like the quick connects). You can also hit the ball on the end of the male connector with a hammer to get it to release a little oil, but I don't like doing that. I'm going to steal an idea someone else poster here and make a tee fitting with two quick connects and a valve. You plug that into the implement when you detach it and use the valve to release any built up pressure.