Auxilary hydraulic lines

[greywynd]

Hi all,

My mini excavator (Hitachi UE-12) has an auxillary circuit, the former owner used it to run a breaker, and I currently use it to run a wood splitter on occasion. It does however have another connection (I'm guessing another supply line) and I'm wondering what the difference is hydraulicly? I'm thinking of building a thumb for it, as well maybe a hydraulic auger for post holes, of course I don't want to go messing up cylinders or hydraulic motors, so want to find out what the difference is with these two lines.

Thanks,
Mark

 

[CascadeScaper]

On older machines a 3rd line is used when running a hoe pac or breaker as the attachment only runs in one direction. This 3rd line is a return-to-tank line that is not connected to a pump outlet. Basically it's sole purpose is to return fluid to the tank as breakers and hoe pacs are single direction operation.

When running a thumb, which is dual directional flow, both lines need to be hooked up to pump outlets to allow fluid to flow in both directions.

Now, on the newer machines, you just throw a lever on the hydraulic pump block and it changes the status of the 2nd line from the traditional 2 way to a 1 way return to tank line, thus removing the need for the 3rd line.

Hope that answered your question.

 

[dirthog]

The older machines also had three lines on them and you could get flow both ways by how the lines at the base of the boom or in the valve bank were hooked up if you are running a wood splitter you are set up for two way flow and as cascade scraper says the third line is more than likley just straight back to tank instead of going through the valve back to tank at least thats how the older kobelco"s were set up

 

[greywynd]

Now you've got me wondering, this has the third connection at the base of the boom, but I never changed it when I hooked it up to the woodsplitter. The way it is now though I know I can switch it either way for the woodsplitter, though I always put it the same way and then use the valve on the splitter. I wonder if the other line connection is the return then that should be used for the breaker? I wonder if there was a chance he was using the wrong connections for his breaker? (previous owner)

Guess I should do some more checking when I get a chance, I want to figure this out before I start building the attachments this winter.

Mark

 

[dirthog]

If you are using the machine to switch direction on the wood spliter it is hooked up now for two way flow if you are using the valve it may or may not be set up that way. On most of the small machines the fittings at the base of the boom it should be marked