Homemade backhoe

[macaldwell]

I was wondering if anyone would be able to help with a problem I am having with my homemade towable backhoe made from a Kubota BT601 hoe attachment? I have matched the hydraulic pump to have the same output as the BX25 tractor that once powered this hoe, but can't get the hoe valve stack to work. This unit has a power beyond built into the hoe valve stack which I am using to power another cylinder and it works just fine, but whenever you try to move any of the hoe control levers it's like they are coming up against a lot of pressure and my 1,500 pound relief valve between the pump and valve stack starts bypassing back to the reservoir. This project has been 5 years in the making and with the new engine and new pump just mounted this weekend.....well you can imagine my frustration when everything works as it should except the hoe. Any ideas or suggests?

 

[Dr Honda]

Is the drain going to a free (no pressure) tank port? Is the power beyond port free flowing? (does it's valve have power beyond?)


Sounds like the low pressure side isn't flowing into "Low pressure".


FYI... I get up to Titusville a couple times a year for an RC jet rally at the airport.

 

[macaldwell]

The tank or reservoir is vented and yes the PB flows freely, I'm using it to power another control valve and cylinder on the unit and it all works well. The low pressure side or what would be considered the return line may very well be the problem but I can't for the likes of me know how or why?

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